What Is Keto?

August 2026 · current as of July 2026

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⚕️ Medical disclaimer

This article is educational, not medical advice. Talk with a doctor before making a big change to how you eat or what you take.

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Most people come to keto because they want to lose weight without feeling hungry all day. For some people, it can help with both, even without counting every calorie.

A ketogenic diet cuts carbohydrates way down — bread, pasta, rice, potatoes, sugar. As glucose and insulin fall, your body begins burning more fat. Your liver also produces ketones, small fuel molecules that your brain and other tissues can use for energy. That change in fuel is the basic idea behind ketosis.

Keto did not begin as a weight-loss plan. Doctors developed the diet about a century ago after observing that fasting could reduce some children’s seizures. The challenge was feeding those children while preserving some of fasting’s metabolic effects. A carefully designed high-fat diet offered a practical way to do that.

Today, people use ketogenic diets for several reasons, while researchers continue studying their wider effects. The rest of this article explains how the fuel switch works, why appetite may become easier to manage, and what the evidence shows about weight, insulin resistance, epilepsy, brain energy, mood, inflammation, and mitochondrial function. It also examines clinical reports of patients reducing medications under medical supervision.

You will see where the evidence is strong, where the questions remain open, and what different forms of keto look like in practice. You will also learn how to approach the diet, measure ketosis, choose foods, and recognize situations that call for professional guidance.

You came for the diet. The real story is bigger — and more hopeful.

You may come to keto for fat loss, fewer cravings, or steadier energy. Those are legitimate reasons to be curious. The larger story begins with a change in fuel.

“Ketogenic” means “ketone-generating.” A ketogenic diet takes carbohydrate way down and puts fat in its place, so your body burns fat and makes ketones. Exact ratios vary. In “Doctor Mike on Diets: Ketogenic Diet,” family physician Doctor Mike—Dr. Mikhail Varshavski, DO, a board-certified family-medicine physician and widely followed online doctor—compares a typical diet of about 50% carbohydrate with a ketogenic diet containing roughly 75% fat, 20% protein, and 5% carbohydrate: “ten times less carbs.”

Doctor Mike supports established uses such as childhood epilepsy and sees potential value for type 2 diabetes, while remaining skeptical of broader claims.

Doctors first developed ketogenic diets roughly a century ago in hospitals for children with severe epilepsy. That medical history led researchers to a wider question: if changing fuel can affect seizures, what else might it change? Current work reaches insulin, brain energy, mitochondria, appetite, body composition, and mental health. Some uses have strong evidence. Others remain early. This article follows those differences through attributed clinician views and primary sources listed below.

For most healthy adults, keto uses ordinary food and can be tried without clinical treatment. Coordinate with a doctor first if you take diabetes or blood-pressure medication, have kidney or liver disease, or are pregnant. Keto may lower glucose or blood pressure enough to require medication adjustments. Therapeutic keto for epilepsy should also be clinician-managed. The clinicians quoted here speak for themselves, not for a single clinical guideline.

The diet gets your attention. The fuel change explains why medicine still cares about it.

It began as a treatment for seizures, not a way to lose weight.

Before modern antiseizure drugs, fasting was one of the few treatments known to reduce seizures in some patients. It could not continue indefinitely, especially for a child.

Around 1921, Mayo Clinic physician Dr. Russell Wilder developed a high-fat, very-low-carbohydrate therapy for epilepsy and coined the term “ketogenic diet.” It lowered glucose and insulin while raising ketones, reproducing much of fasting’s internal state without withholding food. That is why it became known as a “fasting-mimicking” diet.

In their explainer “Is The Ketogenic Diet Good For You?,” the two practicing surgeons behind Talking With Docs credit Wilder with treating “intractable seizures... that they could not control in any other manner.”

The clinical protocol changed little for roughly its first half-century. Doctors used it mainly for children with treatment-resistant epilepsy, often beginning with hospital admission. The Epilepsy Foundation says the classic diet remains “prescribed by a physician and carefully monitored by a dietitian,” typically with a short hospital stay.

After about 100 years of continuous clinical use, the ketogenic diet still treats hard-to-control epilepsy in hospitals, especially in children. It predates most modern seizure drugs.

Its first purpose was changing the brain’s fuel environment. Weight loss came much later.

Ketosis is a fuel switch — a hybrid car changing tanks.

Your body can run on two fuels: sugar and fat. Most of the time it runs on sugar.

Cut carbohydrates low enough, and the sugar tank stops being topped up. Insulin falls. The liver uses its stored sugar, called glycogen. As that supply runs down, fat burning rises and the liver starts making ketones.

Ketones are small fuel molecules, mainly beta-hydroxybutyrate and acetoacetate. Your brain and many other tissues can use them for energy.

If you test, a blood ketone reading around 0.5 mmol/L or higher is the common marker of nutritional ketosis — the controlled state where low carbohydrate and low insulin keep a modest, steady supply of ketones running.

That unit is millimoles per liter, not milliliters. It is simply how much of something is floating in a liter of your blood — the same style of number your doctor uses for cholesterol or blood sugar. Higher means more ketones present; the scale below is what the numbers mean in practice.

Doctor Mike describes the handover in Doctor Mike on Diets: the body “breaks down fats into something known as ketones... and uses those for energy.” He notes that the change “does take a few days.”

The dashboard would look like this:

SUGAR ENGINE — winding down

Carbs are cut, so the tank is no longer being refilled.

FAT ENGINE — running

The liver turns fat into ketones, helping power the body.

Some of that fuel can come from the fat already stored on you. That is the useful part when your goal is weight loss.

When the fat engine becomes the main source of fuel and ketones rise, you are in ketosis.

Remember the word controlled. It separates nutritional ketosis from the condition people often confuse it with.

Why it takes weight off — without a food diary.

Keto can reduce the effort required to eat less. As fat burning rises and insulin falls, appetite often falls too. Dr. Eric Westman, a low-carbohydrate researcher for more than two decades, saw that when patients cut carbohydrates, “they ate less,” and it “became a low-calorie diet even though you didn't have to tell people to eat fewer calories.”

Dr. Ken Berry describes added fat as something that “tweaks your hunger hormones leptin and ghrelin,” leaving many people feeling that “you're just not hungry,” often with fewer meals and less snacking. Some people also report steadier energy without the repeated rise and crash of a high-carbohydrate day.

In 2026, the obvious comparison is with GLP-1 weight-loss drugs such as Ozempic, Wegovy, and Mounjaro. The drugs imitate a gut hormone that signals fullness. Keto may create fullness through a change in fuel. Westman puts the shared effect plainly: “hunger goes down on a shot, hunger goes down on a keto diet.”

The drugs generally work faster and more strongly. In one crossover study, semaglutide reduced daily intake by several hundred calories and lowered visceral fat. A separate low-carbohydrate study found a smaller calorie reduction alongside real fat loss.

Keto also changes what you eat. Westman borrows an image from Dr. Casey Means and Calley Means: medicating a fish does not clean its dirty bowl; you must change the water. That food habit may remain after a prescription ends, although keto also stops working if you abandon it and return to your previous diet.

Early scale loss needs context. Much of it is water, which Doctor Mike calls “a little misleading.” Judge fat loss over weeks. Reviews find meaningful first-year metabolic improvements, but keto is often no better than other diets after twelve months because adherence is difficult.

The conclusion is not “it doesn't work.” It is that “it works by quieting hunger, and the winner is the eating pattern you can actually keep.”

Ketosis is not ketoacidosis — a campfire is not a house fire.

Nutritional ketosis is a gentle, controlled state produced by low-carbohydrate eating or fasting. In a healthy person, blood ketones typically stay around 0.5–3 mmol/L. Your body can use those ketones as fuel while keeping a small amount of insulin available.

That insulin matters. It acts like a brake, holding ketone production low and steady. This is the useful metabolic state a ketogenic diet is designed to produce: controlled access to fat-derived fuel, including fuel your brain can use.

Diabetic ketoacidosis, or DKA, is different. It is a rare, life-threatening emergency found almost always in uncontrolled type-1 diabetes. With too little insulin to apply the brake, ketones can climb to roughly 15–25 mmol/L—about ten times nutritional levels—and the blood becomes acidic.

The surgeons behind Talking With Docs warn that a dietary “ketogenic state” is often confused with “diabetic ketoacidosis... a low pH in your blood which can be fatal.” The difference is control.

· Nutritional ketosis · Diabetic ketoacidosis

--- · --- · ---

Ketones · Low and steady: ~0.5–3 mmol/L · About 15–25 mmol/L, roughly 10× higher

Insulin · Present; brake on · Missing; brake gone

Setting · Healthy low-carb eater or fasting · Uncontrolled type-1 diabetes

Result · Controlled fuel state · Medical emergency; acidic blood

A campfire can provide heat because it stays contained. A house fire runs without control. Ketosis and ketoacidosis sound alike, but treating them as the same condition is the most common mistake in this topic.

Brain Fuel: Insulin is the brake that separates controlled nutritional ketosis from runaway ketoacidosis.

The brain runs on a second fuel — and that was the whole point.

The brain runs on glucose by default, and it runs on ketones too once glucose is scarce. People who stay fat-adapted — including endurance athletes who train and race that way — rely on that second fuel by choice, not as an emergency backup. Talking With Docs explains that after stored sugar runs low, the body can “use fatty acids to convert to ketones,” which the brain draws on “preferentially” because it needs so much energy.

That biology explains why keto was aimed at the brain in the first place. The alternative fuel supply may be one reason the diet can calm seizures.

Claims about healthy brains are less certain. Asked whether keto is “good for the brain,” Doctor Mike says, “the jury’s still out... I need quality research, which I just don’t have.” Some of his patients say they feel foggier on keto, not sharper.

Psychiatrist Dr. Georgia Ede argues that keto may help by changing the brain’s fuel supply and chemistry. That is her clinical view in an emerging field, not settled consensus.

The brain’s ability to use ketones is real. The claim that keto is “great for every brain” has not been proven.

Lower the carbs, and a master hormone called insulin comes down.

Carbohydrates raise blood sugar, prompting insulin to move glucose into cells. Insulin is also the body’s “store energy” or “store it” signal. While it stays high, stored fat is harder to burn. Lowering carbohydrates usually lowers insulin, making that fat easier to access and often easing hunger.

Dr. Annette Bosworth, MD (“Dr. Boz”), is a board-certified internal-medicine physician who has treated insulin resistance with ketogenic diets for more than 20 years. Across her patients, she reports seeing excess insulin years before standard blood-sugar tests become abnormal. That is clinical, observational evidence, not a randomized trial. Saying “it hasn’t been run as an FDA trial” does not make the observation wrong.

Dr. Eric Berg, DC, a chiropractor rather than a physician, teaches a simpler version: “every time you eat you trigger insulin.” He is a popular keto educator who sells supplements and sometimes uses alarm-heavy marketing. Treat that phrase as a beginner’s mental picture and his enthusiastic opinion, not medical evidence.

A keto-adapted person may also respond poorly to a glucose-tolerance test. Dr. Bret Scher and Dr. Eric Westman explain that drinking 75 grams of glucose after avoiding carbohydrates can produce a high, slow-clearing blood-sugar spike while insulin remains low. True insulin resistance usually involves high insulin struggling to push glucose down.

Scher calls this “adaptive glucose sparing,” also known as “physiologic insulin resistance.” A fat-adapted body is temporarily unprepared for a sudden sugar flood. The response commonly normalizes within days to two weeks after carbohydrates return. Diet context therefore matters when interpreting the result.

Context is not permission to dismiss every marker. Cardiovascular risk and cholesterol measures still deserve blood-work review — including LDL, the number people mean when they say “bad cholesterol.” The broader claim that “everyone’s insulin is too high” remains an advocate’s view, not consensus.

Fewer carbohydrates usually mean less insulin—the body’s “store fat” signal—and easier access to stored fuel.

What else clinicians report changing — beyond the scale.

Dr. Ken Berry, MD, lists eleven changes he watches for in his clinic. His most striking reports go well beyond weight loss. Some patients’ blood pressure returned to normal, allowing him to stop one, two, or even three medications. Others improved enough to cancel planned knee-replacement surgery. In one case, fatty liver disappeared on an ultrasound repeated after a year. He also reports less heartburn, steadier moods, calmer appetites, and clearer skin.

Berry connects these changes to lower insulin and less inflammation once sugar and processed carbohydrates come out. His wording matters: “my patients,” not “a trial proved.”

There is a second body of evidence that no trial captures. Two decades of people reporting the same handful of changes — reflux gone, hunger and cravings settled, fatty liver clear on a repeat scan — is not nothing just because nobody funded a study of it. When tens of thousands of people independently report the same result, that is a pattern worth acting on and checking against your own blood work.

The mitochondrial idea also connects with our methylene blue explainer.

Weight loss may bring you in. Better blood pressure, joints, liver health, appetite, and mood may give you reasons to stay.

Cell engines and mood: genuinely exciting, honestly early.

Inside almost every cell are mitochondria: tiny structures that turn food into usable energy. Think of them as the cell’s “power plants.” They also help manage stress and repair.

Some researchers think ketones may provide these cell engines with a steadier, lower-inflammation fuel. Ketosis may also support autophagy, the body’s process for breaking down damaged cell parts—“recycling the garbage in your tissue.” Autophagy is real biology. Whether keto meaningfully increases it in humans is still being studied.

A young field called metabolic psychiatry asks whether brain energy, insulin, and inflammation can affect mental health alongside brain chemistry. Metabolic Mind, led by Dr. Bret Scher, shares studies and striking cases in which ketogenic therapy appeared to help people with serious mental illness after usual treatments had failed. These reports matter, but they are mainly case evidence, not large clinical trials.

The surgeons behind Talking With Docs describe researchers as “positing that it may be beneficial for things like Alzheimer’s, for mood disorders,” while adding that “the research is not totally conclusive.” Much of this work still comes from animals and early human cases.

The cell-engine and mental-health research gives you good reason to keep watching. It does not yet give anyone good reason to replace psychiatric or neurological treatment on their own.

What it looks like to eat this way — including the rough patch.

Cut the sugar and starch way down. Build meals around protein, natural fats, and low-starch vegetables: eggs, fish, meat, olive oil, avocado, nuts, and greens. This does not mean processed “keto” bars. In “The True Ketogenic Diet,” family physician and low-carb advocate Dr. Ken Berry describes a plate as “half... meat and eggs, half... low carb vegetables and then a few nuts and a few berries.” His rule for packaged food is blunter: “if it says keto on the label it’s almost certainly not keto.” That is a purist's standard. For most people the goal is staying in ketosis and losing the weight, and a bar or a packaged snack that keeps you there is not a failure — read the carb count and judge it by whether your own results hold. Harvard notes that keto can emphasize lower-saturated-fat foods such as olive oil, avocado, nuts, and fatty fish.

The first week or two may feel rough. Tiredness, headaches, and mental fog are often called “keto flu.” It is not an illness. Carbohydrate restriction lowers insulin, prompting your kidneys to release more sodium and water. Burning stored carbohydrate, called glycogen, releases more water because each gram had held several grams with it. Sodium, potassium, and magnesium can fall too.

That fluid and mineral loss usually causes the symptoms, rather than fat burning itself. Water, ordinary table or sea salt, and mineral-rich foods may help. You do not need a branded electrolyte drink. Easing into the diet over a week may also make the transition easier.

You do not need strict carnivore eating or multi-day fasts. Start by removing obvious sugar and starch, then choose real foods you can afford and will keep eating. A workable version matters more than someone else’s perfect protocol.

Sticking with keto can still be difficult. Doctor Mike says carbohydrates “have this nasty habit of just sneaking into your foods” and calls the diet “not super sustainable” for long-term weight loss, though potentially useful for a short-term goal. If you take certain medications or have one of the conditions listed earlier, coordinate with your doctor. Otherwise, a healthy adult can sensibly try it.

The 2026 update is simple: begin with ordinary food, replace lost water and minerals, and choose a version you can live with.

Is the keto advice you're following from 2015?

Fitness educator Thomas DeLauer’s “2026 Update” reflects how popular keto advice has changed. He is energetic and hype-forward, so we kept the useful ideas and left out his unsupported figures. This is his practitioner framing, not clinical consensus.

Put protein first. Use dietary fat for fuel and fullness, but remember that body fat also supplies energy.

Do not chase the highest ketone reading. As your body adapts, readings may fall even while you remain in ketosis.

The aim is not to become “anti-carb.” It is to build metabolic flexibility: the ability to use fat or carbohydrate when needed.

Fat quality still matters. Favor foods such as salmon and sardines, especially if heart health concerns you. Keep fiber in the plan through low-carbohydrate vegetables, chia, flax, or psyllium. Continue paying attention to salt and other minerals after the first week.

Give the approach about eight weeks before judging it. Treat keto as a tool, not an identity, and ignore the “keto police” on both sides.

Put protein at the center, stop competing for ketone numbers, and make keto fit your life.

"All that fat and your heart" — genuinely unsettled, shown both ways

The evidence on keto and heart health genuinely points both ways. Much depends on how your body responds.

The American Heart Association, U.S. Dietary Guidelines, and Harvard’s Nutrition Source represent the mainstream-caution position. They warn that saturated fat can raise LDL cholesterol, especially in “hyper-responders.” The American Heart Association says keto “doesn’t meet standards for a healthy diet,” while long-term evidence of benefit remains scarce. Worth knowing: the newest U.S. Dietary Guidelines (2025–2030, released January 2026) dropped the old grain-heavy food pyramid, told people to cut refined carbohydrates and highly processed food, and made more room for protein and full-fat foods. They kept the old limit of 10% of daily calories from saturated fat. So official advice has moved toward part of keto’s case while holding the line on saturated fat. Take it as one input, not the verdict — the verdict is your own blood work.

Keto advocates and some recent reviews emphasize a different result. Keto often lowers triglycerides and can improve other metabolic markers. LDL response also varies enormously between people. From that perspective, saying “it harms hearts” is too broad.

These positions do not carry equal institutional weight. The caution comes from consensus dietary bodies. The counterargument comes mainly from keto-friendly cardiologists, practitioners, and advocates who believe general guidance misses important individual differences.

You can preserve keto’s potential benefits while choosing fats more carefully. Favor olive oil, avocado, nuts, and fish. Use less butter, coconut oil, fatty processed meat, and other concentrated sources of saturated fat.

Get blood work before starting, then repeat it after a few months with your doctor. Track LDL and triglycerides. If LDL rises sharply, you may be a hyper-responder. Change the fats, adjust the diet, or reconsider keto.

Your blood work can show whether keto is helping your metabolic health without pushing LDL in the wrong direction.

How to actually try this — safely, and on your terms

1. Build meals from eggs, fish, meat, olive oil, avocado, nuts, and low-starch vegetables. Dr. Berry’s strict rule is to skip “keto”-labeled packages; if you use one, read the carb count and judge it by your own results. Favoring olive oil, avocado, and fatty fish may also soften heart-health concerns.

2. From day one, drink water and replace salt and minerals. Ease in over a week instead of cutting carbohydrates to zero overnight. That is what keeps the first-week rough patch small.

3. If you take diabetes or blood-pressure medicine, have kidney or liver disease, or are pregnant, ask your doctor: “I want to try low-carb/keto — do we need to adjust my medication first?” A healthy adult without those conditions can start without that medication check.

4. Get blood work before starting and again after a few months, especially LDL and other cholesterol markers. Your results can show whether keto is improving your health without moving LDL the wrong way.

5. Judge every health claim, including this one, by what it does for you — and check anything that sounds too big. The site's fact-check tool copies the prompt for you in one click; paste in the claim and it does the rest.

6. When someone says “keto’s dangerous!” or “keto cures everything!”, point them to the ketosis section above. Send this article with one rule: “Don’t take their word for it — the sources are linked at the bottom. Check them.”

Whole food. Water and minerals. Medication check when needed. Blood work. Source-checking. Then help your people do the same.

Proof It’s The Real Thing

The oldest, best-proven win — with dates and receipts

Keto’s oldest proven use began about a century ago in hospitals. Up to one in three people with epilepsy have seizures medication cannot control. In these difficult cases, a systematic review found that about 56% of children reduced their seizures by more than 50%. Roughly 16% became seizure-free.

The evidence for type 2 diabetes is newer. Dr. Sarah Hallberg, DO, MS—Doctor of Osteopathic Medicine—served as medical director of Medically Supervised Weight Loss at Indiana University Health and at Virta Health. She led a large, peer-reviewed controlled trial comparing a very-low-carbohydrate ketogenic intervention with usual care.

After two years, more than half of the ketogenic-intervention participants were in diabetes remission. Among those who had used insulin, about nine in ten reduced or eliminated it.

These results do not promise that keto will work equally well for everyone. They show why it belongs in serious medical conversations. Its strongest receipts include a century of treating childhood epilepsy and a controlled two-year diabetes trial.

The takeaway: Keto’s best evidence comes from measured medical outcomes, especially fewer childhood seizures and improved type 2 diabetes control.

Don't take our word for it

Every claim above is sourced, and the links are below. The neutral anchors are the Epilepsy Foundation, Johns Hopkins Epilepsy Center, NIH's PubMed and StatPearls, Harvard, the American Heart Association, and the Preventive Cardiovascular Nurses Association.

One standing rule about the voices you heard: physicians, chiropractors, and fitness communicators do not carry equal weight, and each was labeled where they spoke. Credible experience stays in, clearly marked. Nobody's opinion outranks measured results — including ours.

The one thing to take with you: your own blood work beats every opinion on this page, mine included. Test before, test after, and follow your numbers.

Johns Hopkins Epilepsy Center — neutral anchor, primary institution: Dr. Russell Wilder at the Mayo Clinic, 1921, and the coining of “ketogenic diet.”
NIH/PMC — “Ketogenic diet: old treatment, new beginning” — peer-reviewed review: the diet’s origin and its century of continuous clinical use.
Epilepsy Foundation — neutral anchor, professional body: the classic diet “prescribed by a physician and carefully monitored by a dietitian” with a short hospital stay, and its seizure figures (over half of children who go on the diet see seizures cut by at least half; usually 10–15% become seizure-free).
International Ketogenic Diet Study Group, via NIH/PMC — clinical management recommendations for the diet in epilepsy.
Lefevre & Aronson, Pediatrics, 2000, via PubMed — systematic review of 11 studies in children whose seizures medicine could not control: about 56% cut seizures by more than half; 16% became seizure-free.
Child Neurology Foundation — drug-resistant epilepsy — up to 1 in 3 people with epilepsy keep having seizures despite medication.
StatPearls, NCBI/NIH — neutral anchor: evidence-based indications, clinical applications, and the keto-flu mechanism.
Frontiers in Medicine, 2024 — narrative review of keto in clinical populations; where each use sits on the evidence ladder.
Preventive Cardiovascular Nurses Association — professional body, neutral anchor: ketosis versus ketoacidosis, and insulin as the brake.
Diabetes.co.uk — nutritional ketosis at roughly 0.5–3 mmol/L against DKA at roughly 15–25 mmol/L.
ZOE — an independent third source for the same two ranges.
Healthline — keto flu: sodium and water loss, the water released with glycogen, and the salt-and-minerals fix.
Harvard Nutrition Source — consensus anchor carrying the Harvard and American Heart Association caution: saturated fat, LDL, “hyper-responders,” thin long-term evidence; also the lower-saturated-fat foods — olive oil, avocado, nuts, fatty fish.
Harvard Health — the caution side of the heart argument, stated at its strongest.
U.S. Department of Health and Human Services, 7 January 2026 — the 2025–2030 Dietary Guidelines: “eat real food,” cut highly processed food and refined carbohydrates. Harvard’s Nutrition Source notes the 10% saturated-fat limit stayed.
Ketogenic diet and cardiovascular risk — state-of-the-art review — review, the variability side: LDL response differs enormously between people.
American Journal of Clinical Nutrition, 2024 — meta-analysis of cardiovascular risk factors on keto, including triglycerides.
American Heart Association — “Here’s how 10 popular diets scored for heart health” — neutral anchor, professional body: the AHA’s own report on its 2023 scientific statement (Gardner et al., Circulation 2023;147:1715–1730), which placed very-low-carbohydrate/ketogenic eating in the bottom tier for being “high in fat without limiting saturated fat,” and no more effective for long-term weight loss than less restrictive diets. The AHA states this as a tier ranking; the article's wording is a summary, not a quote.
Ge et al., BMJ, 2020 — network meta-analysis of 121 randomized trials, 21,942 adults — peer-reviewed review, the twelve-month claim: low-carbohydrate and low-fat diets produced similar weight loss at six months (4.63 v 4.37 kg), and “at 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear.”
“Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks,” Frontiers in Nutrition, 2021 — peer-reviewed review, the adherence half of that claim: “no advantage was seen relative to control diets in studies of longer duration,” and ketogenic diets “have low long-term tolerability, and are not sustainable for many individuals.”
Blundell et al., Diabetes, Obesity and Metabolism, 2017 — the semaglutide crossover study itself: randomized, double-blind, placebo-controlled, two-period crossover; once-weekly semaglutide escalated to 1.0 mg cut total ad libitum energy intake by 24% (−3036 kJ, roughly 725 calories a day) and reduced body weight by 5.0 kg, “predominantly from body fat mass.”
Cipryan et al., Frontiers in Nutrition, 2021 — randomized controlled trial, the low-carbohydrate side of that comparison: over 12 weeks a very-low-carbohydrate high-fat diet, alone or combined with interval training, cut visceral fat, total body fat and trunk fat, while interval training alone did not.
Miller, Villamena and Volek — “Nutritional Ketosis and Mitohormesis,” Journal of Nutrition and Metabolism, 2018 — peer-reviewed review behind the cell-engine claim: nutritional ketosis increases reliance on mitochondrial respiration, and beta-hydroxybutyrate acts as a signaling molecule and not only as fuel. Stated there as potential, not proven.
Kolb et al., “Ketone bodies: from enemy to friend and guardian angel,” BMC Medicine, 2021 — peer-reviewed review behind the autophagy line: ketone metabolism is proposed to trigger an adaptive response that includes improved mitochondrial function and autophagy. A proposed mechanism, not a measured human outcome.
Youm et al., Nature Medicine, 2015 — the lower-inflammation link: the ketone beta-hydroxybutyrate suppresses the NLRP3 inflammasome. Laboratory and animal work, not a human trial.
Danan, Westman, Saslow and Ede — “The Ketogenic Diet for Refractory Mental Illness,” Frontiers in Psychiatry, 2022 — peer-reviewed retrospective case series, not a randomized trial: 31 hospitalized adults with treatment-refractory major depression, bipolar disorder and schizoaffective disorder; depression and psychosis scores improved substantially. This is the metabolic-psychiatry case evidence described in the mental-health section, and Dr. Georgia Ede is a co-author.
NIH/PMC — Hallberg et al. — the two-year type 2 diabetes study itself: peer-reviewed, non-randomized controlled trial; about 55% in remission, about nine in ten insulin users reduced or eliminated insulin.
Virta Health — Dr. Sarah Hallberg’s credential and role: DO, MS; medical director and principal investigator.
Healio — independent reporting of the same two-year outcomes.
Dr. Annette Bosworth, MD — “Dr. Boz” — documenting clinician, observational: excess insulin years before standard blood-sugar tests turn abnormal.
Healthgrades — Bosworth’s credential and practice: board-certified internal medicine.
Doctor Mike, Dr. Mikhail Varshavski, DO — physician, cautious mainstream: the 75/20/5 ratio and “ten times less carbs,” the few days to switch, water weight as “a little misleading,” “the jury’s still out” on healthy brains, and “not super sustainable.”
Talking With Docs — two practicing surgeons: Wilder and “intractable seizures,” ketones the brain draws on “preferentially,” the ketoacidosis warning, and “the research is not totally conclusive.”
Dr. Ken Berry, MD — physician advocate, clinical account: the plate rule and the keto-label rule, leptin and ghrelin, and the changes he watches for in his own patients.
Dr. Eric Berg, DC — chiropractor, not a physician; sells supplements and markets with alarm: “every time you eat you trigger insulin,” kept as a beginner’s picture and his opinion.
Dr. Eric C. Westman, MD, MHS — Duke Health — credential and role: board-certified in internal medicine, Duke University Medical Center, “committed to reversing chronic medical problems through prescription-strength ketogenic diets.”
Dr. Eric Westman — “Study Compared Ozempic To the Keto Diet! Which is Better For Losing Weight?” — practitioner account, the source of every Westman line in this article: “they ate less,” “it became a low calorie diet even though you didn’t have to tell people to eat fewer calories,” “hunger goes down on a shot. Hunger goes down on a keto diet,” and the dirty-fishbowl image, which he credits to the Means. The side-by-side reading of the drug study and the low-carbohydrate study is his own; as he says in the video, no randomized trial has yet pitted a keto diet directly against a GLP-1.
Dr. Westman Reacts: Insulin Resistance on Keto — practitioner account: why low insulin on a keto diet is not the pathologic insulin resistance the same test would signal on a high-carbohydrate diet.
Metabolic Mind — “Is Keto Linked to Insulin Resistance? What the Research Says” — practitioner account, Dr. Bret Scher on camera: the 75-gram oral glucose tolerance test, the terms “adaptive glucose sparing” and “physiologic insulin resistance,” and the normalization once carbohydrate is ramped back up over three days to two weeks.
Dr. Bret Scher, MD — Metabolic Mind — credential and role: board-certified cardiologist and lipidologist, Medical Director of Metabolic Mind, a non-profit initiative of the Baszucki Group.
Dr. Georgia Ede, MD — credential: Harvard-trained, board-certified psychiatrist working in nutritional and metabolic psychiatry, whose stated subject is “the inner workings of the brain and its metabolism.” Her position here is an attributed clinical view in an emerging field, not consensus.
Thomas DeLauer — “The New Era of Keto in 2026 (NEW science, NEW rules)” — fitness educator, practitioner framing rather than clinical consensus: protein first with fat as fuel, do not chase the highest ketone reading, metabolic flexibility over being anti-carb, and about eight weeks before judging it.
Casey and Calley Means — who the fishbowl image comes from: Casey Means holds an MD; Calley Means holds a BA and an MBA and is not a physician. They co-wrote Good Energy (2024). The image reaches this article second-hand, through Westman.

This is the whole article, taught from zero, one section at a time. Above each section, a blue box tells you in plain words what that section is about to show you. Where a section leans on a hard idea or number, a second box takes that idea apart before you go on.

You will see some of the same sentences and numbers here as in the article. That is expected: this side covers the same facts, but explains each idea first, one step at a time.

💡 Before you read this part

Below, the article starts with why most people try keto: to lose weight without feeling hungry all day. Then it says what keto is. You cut way back on bread, pasta, rice, potatoes and sugar, and your body starts burning more fat. Your liver also makes a small fuel out of fat that your brain can use. Next comes a surprise: keto did not start as a weight-loss diet at all. It started about a hundred years ago, as a way to help children who had seizures. The section ends with a list of what the rest of the article covers, from how the fuel switch works to when you need a doctor.

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The two words to learn first are glucose and insulin. Carbohydrates are the starchy and sweet foods, like bread, pasta, rice, potatoes and sugar. Your body breaks them down into a sugar called glucose, the fuel it burns first. Insulin is a hormone, which means a chemical message your body sends through the blood. Picture every cell in your body with a locked door. Glucose waits outside, in the blood. Insulin is the key that opens the door so the sugar can get in. Insulin also has a second job: it tells the body to store energy for later. While there is a lot of insulin around, stored fat stays hard to reach. So the chain goes like this. Eat bread or sugar, and glucose goes up, so insulin goes up. Eat very few carbohydrates, and glucose stays low, so insulin comes down, and stored fat gets easier to burn.

Start Here

What’s in the rest of this article?

Most people try keto for one reason. They want to lose weight without feeling hungry all day. For some people, keto can help with both, even without counting every calorie.

Keto means cutting carbohydrates way down: bread, pasta, rice, potatoes, sugar. When you do that, glucose and insulin in your blood go down. Then your body starts burning more fat.

Your liver also starts making ketones. The liver is a large organ on the right side of your belly that stores and handles fuel. Ketones are small fuel molecules. Your brain and other parts of your body can burn them for energy. That change of fuel is the basic idea behind ketosis.

Keto did not start as a way to lose weight. About a hundred years ago, doctors saw that fasting, which means going without food, could cut down seizures in some children. A seizure is a sudden burst of electrical activity in the brain that can make a person shake, stare or pass out.

But a child cannot go without food for long. So doctors needed a way to feed those children and still get some of fasting’s effects inside the body. A carefully planned high-fat diet did that.

Today people use keto for many reasons, and scientists are still studying what else it does. The article walks through how the fuel switch works and why hunger may get easier to handle. Then it looks at the evidence on weight, on insulin resistance (a body that needs more and more insulin to do the same job), on epilepsy (the illness that causes repeated seizures), on brain energy, mood and inflammation, and on the tiny parts inside cells that make energy. It also looks at doctors’ reports of patients cutting back medicines with a doctor watching.

You will see where the evidence is strong and where questions are still open. You will also learn how to start, how to measure ketosis, what to eat, and when to bring in a doctor.

💡 Before you read this part

Below, the article explains the word itself. Ketogenic means ketone-making: a diet that gets your body making ketones. Then Doctor Mike, a family doctor with a big online following, puts numbers on it. A normal diet is about half carbohydrate. A keto diet is mostly fat, some protein, and only a sliver of carbohydrate, which he calls ten times less. He backs keto for children with epilepsy, thinks it may help type 2 diabetes, and doubts the bigger promises. After that comes the question that makes the story bigger: if changing fuel can calm seizures, what else can it change? The section ends by saying when to check with a doctor before starting: if you take diabetes or blood-pressure medicine, have kidney or liver disease, or are pregnant.

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Doctor Mike’s numbers are easier to see as pieces. Picture everything you eat in a day split into 20 equal pieces. On a typical diet, about 10 of those pieces are carbohydrate. That is his 50%. On a ketogenic diet, 15 pieces are fat, 4 are protein, and 1 is carbohydrate. That is his 75%, 20% and 5%. Carbohydrate goes from 10 pieces down to 1, which is ten times less.

Why It Matters

You came for the diet. The real story is bigger.

You might come to keto to lose fat, to have fewer cravings, or to have steadier energy. Those are good reasons to be curious. The bigger story starts with a change in the fuel your body burns.

A ketogenic diet cuts carbohydrate way down and puts fat in its place. Your body then burns fat and makes ketones. The exact amounts vary.

Doctor Mike is Dr. Mikhail Varshavski, a board-certified family doctor and a widely followed online doctor. His degree is a Doctor of Osteopathic Medicine. In his video “Doctor Mike on Diets: Ketogenic Diet,” he compares two diets. A typical diet is about 50% carbohydrate. A ketogenic diet is roughly 75% fat, 20% protein and 5% carbohydrate. In his words, that is “ten times less carbs.”

Doctor Mike backs the uses that are well established, like treating epilepsy in children. He sees possible value for type 2 diabetes. That is the common kind of diabetes, where blood sugar stays too high because the body stops responding well to insulin. He doubts the bigger claims.

Doctors first used ketogenic diets about a hundred years ago, in hospitals, for children with severe epilepsy. That history led researchers to a bigger question. If changing the fuel can change seizures, what else might it change?

Today the research reaches insulin, brain energy, appetite, mental health, and how much of the body is fat and how much is muscle. It also reaches mitochondria, the tiny parts inside cells that make energy. Some of these uses have strong evidence. Others are early. The article keeps them apart and says which doctor holds which view, with the main sources named.

For most healthy adults, keto is ordinary food, and you can try it without a doctor running it. But talk to a doctor first if you take medicine for diabetes or blood pressure, if you have kidney or liver disease, or if you are pregnant. Keto can lower blood sugar or blood pressure enough that a medicine dose needs changing. Keto used to treat epilepsy should also be run by a doctor.

The doctors quoted in this article speak for themselves. They do not speak for one official set of medical rules.

💡 Before you read this part

Below is where keto came from. Before there were good seizure medicines, doctors knew that fasting, going without food, could calm some seizures. But a child cannot fast for long. Around 1921, Dr. Russell Wilder at the Mayo Clinic found an answer: a diet so high in fat and so low in carbohydrate that the body acts as if it is fasting while the child still eats. That is why it was called fasting-mimicking. Two surgeons from Talking With Docs say it helped seizures that nothing else could stop. Watch the last part, because it is not old history. Hospitals still use the diet today for children whose seizures medicine cannot control, and the Epilepsy Foundation says a doctor and a food expert still run it.

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How can a full plate copy a fast? When you go without food, your body runs low on sugar. Glucose and insulin drop, and the liver starts making ketones. Now picture a plate with almost no bread, rice, potatoes or sugar on it, and lots of fat instead. The child is fed, but the body still gets almost no sugar. So glucose and insulin stay low and ketones rise, the same as in a fast. That is what Dr. Russell Wilder found: the inside of a fast, with food on the table.

The Origin

It began as a treatment for seizures, not a way to lose weight.

Before modern seizure medicines existed, fasting was one of the few treatments known to cut down seizures in some patients. But nobody can fast forever, and a child least of all.

Around 1921, Dr. Russell Wilder, a doctor at the Mayo Clinic, created a treatment for epilepsy. It was a diet very high in fat and very low in carbohydrate. He also gave it its name: the “ketogenic diet.”

The diet lowered glucose and insulin and raised ketones. That copied much of what fasting does inside the body, without taking food away. So it became known as a “fasting-mimicking” diet. Mimicking means copying.

Talking With Docs is run by two practicing surgeons. In their explainer “Is The Ketogenic Diet Good For You?,” they credit Wilder with treating “intractable seizures... that they could not control in any other manner.” Intractable means nothing else would stop them.

For about its first fifty years, doctors changed the diet very little. They used it mostly for children whose epilepsy medicine could not control. Treatment often began with a stay in the hospital.

The Epilepsy Foundation says the classic diet is still “prescribed by a physician and carefully monitored by a dietitian,” usually with a short hospital stay. A dietitian is an expert in food and nutrition.

After about 100 years of steady use, hospitals still use the ketogenic diet to treat hard-to-control epilepsy, especially in children. It is older than most of today’s seizure medicines.

Its first job was to change the fuel the brain runs on. Weight loss came much later.

💡 Before you read this part

Below, the article explains the switch with a hybrid car that has two tanks, one for sugar and one for fat. Cut carbohydrates and the sugar tank stops getting refilled. Insulin drops. The liver first uses up its own small store of sugar, called glycogen, and then starts turning fat into ketones. Ketones have long chemical names, and you do not need to remember them. Then comes a number: a blood test reading of 0.5 or higher means you are in ketosis. The article explains the odd unit that goes with it, and Doctor Mike says the switch takes a few days. The section ends on the word controlled. Hold on to that word, because it matters two sections from now.

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A ketone test measures how many ketones are floating in your blood, and the number works like a ladder. Below 0.5 is under the usual line for ketosis. From 0.5 up to about 3 is nutritional ketosis, the normal range for a healthy person eating low-carb. Far above that, at about 15 to 25, is diabetic ketoacidosis, a medical emergency, around ten times higher than nutritional ketosis. The unit, mmol/L, counts tiny molecules in each liter of blood; a liter is about one large water bottle. The big jump between the middle of the ladder and the top is what the section after next is about.

The Switch

Ketosis is a fuel switch — a hybrid car changing tanks.

Your body can run on two fuels: sugar and fat. Most of the time it runs on sugar. Think of a hybrid car with two tanks, one for sugar and one for fat.

Cut carbohydrates low enough and the sugar tank stops getting refilled. Insulin falls. The liver uses up its stored sugar, glycogen. As that store runs down, the body burns more fat, and the liver starts making ketones.

Ketones are small fuel molecules. The two main ones have long chemical names: beta-hydroxybutyrate and acetoacetate. Your brain and many other parts of your body can burn them for energy.

You can test for them. A blood ketone reading of about 0.5 mmol/L or higher is the usual sign of nutritional ketosis. That is the controlled state where low carbohydrate and low insulin keep a small, steady supply of ketones flowing.

The unit, mmol/L, means millimoles per liter, not milliliters. It is just how much of something is floating in a liter of your blood. Your doctor uses the same kind of number for cholesterol and blood sugar. A higher number means more ketones.

In “Doctor Mike on Diets,” Doctor Mike describes the handover. The body “breaks down fats into something known as ketones... and uses those for energy.” He notes that the change “does take a few days.”

If your body had a dashboard, it would show two lights. The sugar engine is slowing down, because carbs are cut and its tank is not being refilled. The fat engine is running, because the liver is turning fat into ketones to help power the body.

Some of that fat can come from the fat already stored on your body. That is the part that helps with weight loss.

When fat becomes your main fuel and ketones rise, you are in ketosis.

Keep one word in mind: controlled. It is what separates nutritional ketosis from a dangerous condition with a very similar name.

💡 Before you read this part

Below, the article answers the question most people care about: why would keto take weight off if you are not counting food? The answer is hunger. Dr. Eric Westman saw that patients who cut carbohydrates simply ate less, without being told to. Dr. Ken Berry says added fat calms two hunger hormones. Then keto is set next to the weight-loss shots, like Ozempic, Wegovy and Mounjaro, and the article is fair about it: the shots work faster and harder. Dr. Casey Means and Calley Means add a picture about a fish in a dirty bowl. Watch the warning near the end. The first weight you lose is mostly water, and after a year keto often does no better than other diets, because it is hard to stick with.

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Why does the scale drop so fast in the first week or two? Picture glycogen, your stored sugar, as a wet sponge. Each gram of glycogen holds several grams of water with it. When keto uses up the glycogen, the water it was holding goes too, and your kidneys send it out of the body. So the scale can fall quickly even though very little fat is gone yet. Fat comes off more slowly. That is why the article says to judge fat loss over weeks, and why Doctor Mike calls the early number “a little misleading.”

The Appetite

Why it takes weight off — without a food diary.

Keto can make eating less take less effort. As fat burning rises and insulin falls, appetite often falls too.

Dr. Eric Westman has researched low-carbohydrate eating for more than twenty years. He saw that when patients cut carbohydrates, “they ate less.” It “became a low-calorie diet even though you didn't have to tell people to eat fewer calories.”

Dr. Ken Berry says added fat “tweaks your hunger hormones leptin and ghrelin.” Leptin is the hormone that tells your brain the body has enough stored energy. Ghrelin is the hormone that makes you feel hungry. Many people end up feeling that “you're just not hungry.” They often eat fewer meals and snack less.

Some people also say their energy is steadier. They skip the rise and crash that can come with a day of high-carbohydrate meals.

In 2026, keto gets compared with the GLP-1 weight-loss drugs, such as Ozempic, Wegovy and Mounjaro. GLP-1 is a hormone your gut makes to signal that you are full. The drugs copy it. Keto may create the same full feeling a different way, through the change in fuel. Westman says: “hunger goes down on a shot, hunger goes down on a keto diet.”

The drugs usually work faster and more strongly. One crossover study had the same people try each option in turn. In it, semaglutide, the medicine in Ozempic and Wegovy, cut daily eating by several hundred calories. It also reduced visceral fat, the fat packed around the organs inside the belly. Another low-carbohydrate study found a smaller drop in calories, along with real fat loss.

Keto also changes what you eat. Westman borrows a picture from Dr. Casey Means and Calley Means: giving medicine to a fish does not clean its dirty bowl; you have to change the water. The eating habit may stay with you after a prescription ends. But keto also stops working if you quit and go back to your old way of eating.

Early weight loss on the scale needs care. Much of it is water. Judge fat loss over weeks. Reviews, which pool the results of many studies, find real improvements in the body’s fuel handling in the first year. But after twelve months, keto often does no better than other diets, because people find it hard to stick with.

So the conclusion is not “it doesn't work.” It is that “it works by quieting hunger, and the winner is the eating pattern you can actually keep.”

💡 Before you read this part

Below, the article clears up the biggest mix-up about keto. Two words sound almost the same. Nutritional ketosis is the mild state keto puts you in: ketones between about 0.5 and 3, with a little insulin still around. Diabetic ketoacidosis, or DKA, is a rare emergency. It happens almost only in type 1 diabetes, where the body makes little or no insulin of its own, when that diabetes is out of control. With no insulin to slow things down, ketones climb to 15 to 25, about ten times higher, and the blood turns acidic. The surgeons from Talking With Docs warn that people confuse the two. A table puts them side by side, and a campfire and a house fire show the difference.

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Why does missing insulin let ketones run away, and why is acidic blood an emergency? Think of insulin as a brake on ketone making. In ketosis the brake is on, lightly, so ketones stay low and steady. In type 1 diabetes that is out of control, the brake is gone. Ketones are acids, mild ones. That is the “acid” in keto-acid-osis, and -osis means too much of something. With the brake gone, ketones pile up until the blood itself turns acidic. The body’s chemistry only works when the blood stays inside a narrow range, so that is what makes it life-threatening. The surgeons behind Talking With Docs call it “a low pH in your blood which can be fatal.” pH is the scale for how acidic something is. The lower the pH, the more acidic.

The Confusion

Ketosis is not ketoacidosis — a campfire is not a house fire.

Nutritional ketosis is a gentle, controlled state. You get there by eating low-carbohydrate or by fasting. In a healthy person, blood ketones usually stay around 0.5 to 3 mmol/L. Your body burns those ketones as fuel and still keeps a small amount of insulin around.

That insulin matters. It works like a brake, keeping ketone making low and steady. This is the state a ketogenic diet is designed to create: controlled use of fuel made from fat, including fuel your brain can use.

Diabetic ketoacidosis, called DKA for short, is different. It is a rare, life-threatening emergency. It happens almost always in type 1 diabetes that is not under control. Without enough insulin to work the brake, ketones can climb to about 15 to 25 mmol/L. That is about ten times the level in nutritional ketosis, and the blood turns acidic.

The surgeons behind Talking With Docs warn that a diet’s “ketogenic state” often gets confused with “diabetic ketoacidosis... a low pH in your blood which can be fatal.” The difference is control.

A campfire can give you heat because it stays contained. A house fire burns with nothing holding it in. Ketosis and ketoacidosis sound alike, but treating them as the same thing is the most common mistake people make on this topic.

	Nutritional ketosis	Diabetic ketoacidosis
Ketones	Low and steady: about 0.5–3 mmol/L	About 15–25 mmol/L, roughly 10× higher
Insulin	Present; brake on	Missing; brake gone
Setting	Healthy low-carb eater or fasting	Uncontrolled type 1 diabetes
Result	Controlled fuel state	Medical emergency; acidic blood

💡 Before you read this part

Below, the article comes back to the brain, where keto started. Your brain normally burns glucose, but when glucose runs short it can burn ketones. Some people run on that second fuel on purpose, like endurance athletes who race long distances. The surgeons from Talking With Docs say the brain reaches for ketones first when it has them, because it needs so much energy. That second fuel may be part of why the diet calms seizures. Then the article slows down. Doctor Mike is asked if keto is good for the brain and says the jury is still out, and some of his patients feel foggier on it. Psychiatrist Dr. Georgia Ede thinks it may help mental health, and the article marks that as her view, not a settled fact.

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Two claims get mixed up here, and they are different kinds of claim. The first is that the brain can burn ketones. That is about how the body works, and it is known. The second is that keto makes a healthy brain work better. That is a promise about results, and proving it takes careful studies that compare people on keto with people who are not. Doctor Mike says he does not have that kind of research. A body being able to do something does not show that doing it makes you sharper.

The Brain

The brain runs on a second fuel — and that was the whole point.

The brain runs on glucose by default. When glucose is scarce, it runs on ketones too.

Some people stay fat-adapted, which means their bodies are used to running on fat. That includes endurance athletes, the people who race long distances, when they train and race that way. They use the second fuel by choice, not as an emergency backup.

Talking With Docs explains that after stored sugar runs low, the body can “use fatty acids to convert to ketones.” Fatty acids are the building blocks of fat. The brain draws on those ketones “preferentially,” meaning it picks them first, because it needs so much energy.

That is why keto was aimed at the brain from the start. Having a second fuel supply may be one reason the diet can calm seizures.

Claims about healthy brains are less certain. Asked whether keto is “good for the brain,” Doctor Mike says, “the jury’s still out... I need quality research, which I just don’t have.” “The jury’s still out” means nobody has decided yet. Some of his patients say they feel foggier on keto, not sharper.

Dr. Georgia Ede is a psychiatrist, a medical doctor who treats mental illness. She argues that keto may help by changing the brain’s fuel supply and chemistry. That is her view from treating patients in a new field. It is not settled, and most experts have not agreed on it yet.

So the brain really can use ketones. The claim that keto is “great for every brain” has not been proven.

💡 Before you read this part

Below, the article gets to insulin, the hormone this whole topic turns on. Eat carbohydrates and your blood sugar rises. Insulin moves that sugar into your cells, and it also tells your body to store energy, so stored fat stays hard to burn. Eat fewer carbohydrates and insulin usually drops. Then come three voices. Dr. Annette Bosworth, called Dr. Boz, says that in 20 years of patients she sees too much insulin long before sugar tests look wrong, and the article labels that as what she saw, not a trial. Dr. Eric Berg, a chiropractor who sells supplements, gives a simpler line that the article says to treat as a beginner’s picture. Then Dr. Bret Scher and Dr. Eric Westman explain a trap: a common sugar test can look bad for a keto eater for a harmless reason.

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This is the trap Dr. Bret Scher and Dr. Eric Westman describe. It is in a common test called the glucose-tolerance test: you drink 75 grams of glucose, and your blood sugar is measured afterward. Picture a bakery that has not had a flour delivery in weeks. Its bakers have been moved to other jobs. Then a truck dumps a whole load of flour at the back door. The flour piles up outside for a while. The bakery is fine. Nobody was ready for it, and within days the bakers are back. That is a body used to keto taking the test: sugar piles up in the blood, insulin stays low, and the result looks bad. Real insulin resistance looks different. The bakers are all there and working hard, which means insulin is high, and the flour still piles up. So a high sugar reading with low insulin, right after weeks of keto, may just mean the body was not expecting sugar.

The Hormone

Lower the carbs, and a master hormone called insulin comes down.

Carbohydrates raise the sugar in your blood. That makes your body release insulin, which moves the sugar into your cells. Insulin is also the body’s “store energy” or “store it” signal. While insulin stays high, stored fat is harder to burn.

Eating fewer carbohydrates usually lowers insulin. That makes stored fat easier to reach, and it often makes hunger easier too.

Dr. Annette Bosworth, MD, is known as “Dr. Boz.” She is a board-certified internal-medicine doctor, which means a doctor for adults. She has treated insulin resistance with ketogenic diets for more than 20 years. Across her patients, she reports seeing too much insulin years before standard blood-sugar tests turn abnormal.

That is evidence from watching her own patients. It is not a randomized trial, the kind of study that splits people into groups by chance and compares them. But saying “it hasn’t been run as an FDA trial” does not make what she saw wrong. The FDA is the U.S. agency that approves medicines.

Dr. Eric Berg is a chiropractor, not a medical doctor. Chiropractors mainly treat the spine and joints. He teaches a simpler version: “every time you eat you trigger insulin.” He is a popular keto teacher who sells supplements and sometimes uses alarming marketing. Treat that line as a beginner’s picture and his own excited opinion, not as medical evidence.

There is also a trap in the glucose-tolerance test, where you drink 75 grams of glucose. Dr. Bret Scher and Dr. Eric Westman explain what happens to someone who has been avoiding carbohydrates. Their blood sugar can spike high and come down slowly, while their insulin stays low. True insulin resistance usually looks different: high insulin struggling to push the sugar down.

Scher calls this “adaptive glucose sparing.” It is also called “physiologic insulin resistance.” Physiologic means it is the body’s normal response, not a disease. A body used to running on fat is, for a while, not ready for a sudden flood of sugar. The response usually goes back to normal within days to two weeks after carbohydrates come back. So what you have been eating matters when you look at the result.

That does not mean every warning number can be ignored. Heart risk and cholesterol numbers still need checking in blood work. That includes LDL, the number people mean when they say “bad cholesterol.” And the bigger claim that “everyone’s insulin is too high” is the view of keto supporters, not something most experts agree on.

💡 Before you read this part

Below, Dr. Ken Berry lists what he says changes in his own patients, beyond weight. Some had blood pressure go back to normal, so he could stop one, two or three medicines. Some got well enough to cancel knee surgery. One had a fatty liver that was gone on a scan a year later. He also sees less heartburn, better moods, calmer appetites and clearer skin. He thinks lower insulin and less inflammation, the body’s irritation response, are behind it. Watch how he words it: these are his patients, not a trial. Then the article makes a case for listening anyway. When tens of thousands of people report the same few changes, it calls that a pattern worth acting on, and worth checking in your own blood work.

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One doctor’s patients, many people’s reports, and a trial are three different kinds of evidence. When one doctor sees a change in his own patients, it might be luck, or the kind of patients he happens to have. When tens of thousands of people separately report the same few changes, luck gets harder to believe. A trial goes one step further. It gives the treatment to one group and not to another, then compares them, so it can show that the treatment caused the change. Dr. Ken Berry’s reports are the first kind, and the article says so. The practical answer is the one it gives: check the change in your own blood work.

The Clinic Reports

What else clinicians report changing — beyond the scale.

Dr. Ken Berry, MD, lists eleven changes he watches for in his clinic. His most striking reports go far beyond weight loss.

In some patients, blood pressure came back down to normal, so he could stop one, two, or even three medicines. Others got well enough to cancel planned knee-replacement surgery.

In one patient, fatty liver, which is fat built up inside the liver, was gone on an ultrasound repeated after a year. An ultrasound is a scan that uses sound waves to see inside the body.

He also reports less heartburn, steadier moods, calmer appetites and clearer skin.

Berry links these changes to lower insulin and less inflammation once sugar and processed carbohydrates come out of the diet. Inflammation is the body’s response to injury or irritation, like the redness and swelling around a cut. His wording matters: “my patients,” not “a trial proved.”

There is a second kind of evidence that no trial captures. For two decades, people have reported the same few changes: reflux gone, hunger and cravings settled, fatty liver clear on a repeat scan. Reflux is stomach acid coming back up into the throat.

Those reports are not nothing just because nobody paid for a study of them. When tens of thousands of people separately report the same result, the article calls that a pattern worth acting on, and worth checking against your own blood work.

Weight loss may be what brings you in. Better blood pressure, joints, liver health, appetite and mood may be what makes you stay.

💡 Before you read this part

Below is the newest and least certain research. It starts with mitochondria, the tiny power plants inside almost every cell that turn food into energy. Some researchers think ketones give them a steadier fuel that causes less inflammation. Keto may also help autophagy, the body’s way of recycling broken cell parts, though that is still being tested in people. Then comes a young field called metabolic psychiatry, which asks whether the brain’s energy supply plays a part in mental illness. Metabolic Mind, led by Dr. Bret Scher, shares striking cases where keto seemed to help after other treatments failed. The surgeons from Talking With Docs mention Alzheimer’s and mood disorders. Watch the verdict at the end: worth watching, and not yet a reason to change anyone’s treatment on your own.

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Why “early” is the right word. Medical research climbs a ladder. The first rungs are studies in cells and in animals, like mice. Next come single striking cases: one person who got better. Then small studies of a few people. At the top are large trials that compare many people split into groups by chance. Much of the work on ketones and mental health is still on the lower rungs, in animals and early human cases. The striking cases Metabolic Mind shares sit on the second rung. A result on a low rung can be real and still fail to hold up higher on the ladder. That is why the advice here is to keep watching, and not to change any treatment on your own.

The Early Science

Cell engines and mood: exciting, and early.

Inside almost every cell are mitochondria. These tiny parts turn food into energy the cell can use. Think of them as the cell’s “power plants.” They also help the cell handle stress and make repairs.

Some researchers think ketones may give these power plants a steadier fuel that causes less inflammation.

Ketosis may also help with autophagy. Autophagy is the body’s way of breaking down the damaged parts of cells, or “recycling the garbage in your tissue.” Autophagy is real biology. Whether keto increases it enough to matter in people is still being studied.

A young field called metabolic psychiatry asks a new question. Can brain energy, insulin and inflammation play a part in mental health, alongside brain chemistry?

Metabolic Mind, led by Dr. Bret Scher, shares studies and striking cases. In them, ketogenic therapy seemed to help people with serious mental illness after the usual treatments had failed. Those reports matter. But they are mainly case evidence, meaning stories of single patients, not large clinical trials.

The surgeons behind Talking With Docs say researchers are “positing that it may be beneficial for things like Alzheimer’s, for mood disorders.” Positing means suggesting. Alzheimer’s is a disease that slowly destroys memory. They add that “the research is not totally conclusive.” Much of this work still comes from animals and early human cases.

This research is a good reason to keep watching. It is not yet a good reason for anyone to replace psychiatric or neurological treatment on their own. Psychiatric treatment is for mental illness. Neurological treatment is for the brain and nerves, such as epilepsy.

💡 Before you read this part

Below, the article gets practical. Build meals from protein, natural fats and vegetables that are low in starch: eggs, fish, meat, olive oil, avocado, nuts and greens. Dr. Ken Berry describes his plate and says anything labeled keto is almost certainly not. The article answers him: that is the strictest view, and a packaged snack that keeps you in ketosis is fine if your results hold. Harvard points to foods lower in the kind of fat that raises heart worries. Then comes the rough first week, called keto flu: tiredness and headaches that come mostly from losing water and salt, not from burning fat. Water, salt and easing in help. The section ends with Doctor Mike, who says carbohydrates sneak into food and keto is hard to keep up for years.

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Why would losing salt make you feel sick? Your blood carries salts and minerals: sodium, the main part of table salt, plus potassium and magnesium. Your nerves and muscles need them to send signals and to work. When insulin drops, your kidneys let go of more sodium, and water goes with it. Burning glycogen lets go of the water it was holding, too. So in the first week you can end up short of both water and salts, and you feel it: tired, headachy, foggy. Put the water and salt back and the rough patch usually shrinks. That is why the article’s answer is plain water and ordinary salt, not a special drink.

The Practice

What it looks like to eat this way — including the rough patch.

Cut sugar and starch way down. Starch is the filling part of foods like bread, rice, pasta and potatoes. Build meals around protein, natural fats and low-starch vegetables: eggs, fish, meat, olive oil, avocado, nuts and greens. This does not mean processed “keto” bars.

Dr. Ken Berry is a family doctor who argues for low-carb eating. In “The True Ketogenic Diet,” he describes the plate as “half... meat and eggs, half... low carb vegetables and then a few nuts and a few berries.” His rule for packaged food is blunter: “if it says keto on the label it’s almost certainly not keto.”

That is a purist’s standard. A purist wants things done the strictest possible way. For most people, the goal is staying in ketosis and losing the weight. A bar or packaged snack that keeps you there is not a failure. Check the carb count, and judge it by whether your own results hold.

Harvard notes that keto can lean on foods lower in saturated fat, such as olive oil, avocado, nuts and fatty fish. Saturated fat is the kind that stays solid at room temperature, like butter.

The first week or two may feel rough. Tiredness, headaches and a foggy head are often called “keto flu.” It is not an illness.

Here is the cause. Cutting carbohydrates lowers insulin, and that makes your kidneys let go of more sodium and water. Burning through stored sugar, glycogen, lets go of more water, because each gram of it was holding several grams of water. Sodium, potassium and magnesium can drop too.

That loss of water and minerals usually causes the symptoms, rather than the fat burning. Water, ordinary table or sea salt, and foods rich in minerals may help. You do not need a branded electrolyte drink, the kind sold to replace those salts. Easing into the diet over a week may also make the change easier.

You do not need to eat only meat, the way strict carnivore eaters do, or to fast for days at a time. Start by removing the obvious sugar and starch. Then pick real foods you can afford and will keep eating. A version you can keep up matters more than someone else’s perfect plan.

Sticking with keto can still be hard. Doctor Mike says carbohydrates “have this nasty habit of just sneaking into your foods.” He calls the diet “not super sustainable” for long-term weight loss, meaning hard to keep up for years, though it may be useful for a short-term goal.

If you take certain medicines or have one of the conditions listed near the start, work with your doctor. Otherwise, a healthy adult can sensibly try it.

💡 Before you read this part

Below, the article updates old keto advice using fitness teacher Thomas DeLauer’s “2026 Update.” He leans toward hype, so the article kept his useful ideas and left out his numbers. The ideas come one at a time. Put protein first, and remember the fat on your body is fuel too. Do not chase the highest ketone reading, because the number can drop while you are still in ketosis. Aim to be able to burn either fuel, instead of treating carbohydrate as the enemy. Pick fish like salmon and sardines, keep fiber in, and keep up the salt. Give it about eight weeks, and ignore the people on either side who say there is only one right way.

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Metabolic flexibility means your body can burn fat or carbohydrate, whichever is there, and switch between them easily, like the hybrid car earlier in the article that can use either tank. A body that can only burn one fuel well gets stuck when that fuel runs short. The newer advice from Thomas DeLauer aims for that switch. It does not aim for a body that can only burn fat, and it does not aim for the biggest possible ketone number.

The Update

Is the keto advice you’re following from 2015?

Fitness teacher Thomas DeLauer’s “2026 Update” shows how popular keto advice has changed. He is energetic and leans toward hype, so the article kept his useful ideas and left out his unsupported figures. This is his view from working with people, not what doctors as a group agree on.

Put protein first. Use fat from food for fuel and to feel full. But remember that the fat on your body is fuel too.

Do not chase the highest ketone reading. As your body adapts, the reading may fall even while you are still in ketosis.

The aim is not to be “anti-carb.” It is metabolic flexibility: being able to use fat or carbohydrate when needed.

The kind of fat still matters. Choose foods like salmon and sardines, especially if you worry about your heart.

Keep fiber in the plan. Fiber is the part of plant food your body cannot break down. It can come from low-carbohydrate vegetables, chia, flax or psyllium. Chia and flax are small seeds. Psyllium is a plant husk sold as a fiber powder.

Keep paying attention to salt and other minerals after the first week.

Give it about eight weeks before you judge whether it works. Treat keto as a tool, not as who you are. And ignore the “keto police” on both sides, the people who insist there is only one right way to eat.

💡 Before you read this part

Below is the part of keto that is still unsettled: what all that fat does to your heart. A heart blood test shows a few numbers. LDL is the one people call bad cholesterol. Triglycerides are the fat floating in your blood. The American Heart Association, the U.S. Dietary Guidelines and Harvard warn that the fat in foods like butter and fatty meat can push LDL up, especially in some people. Keto supporters answer that keto often brings triglycerides down, and that LDL moves very differently from person to person. The article says the two sides do not carry equal official weight. Then it gives you the part you can act on: which fats to choose, and blood work before and after, so your own numbers decide.

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Say two people start keto on the same day. Both get blood work before they start and again a few months in. The first person’s LDL barely moves. The second person’s LDL jumps sharply. Same diet, different bodies. The second person may be what doctors call a hyper-responder, the kind of person the American Heart Association warns about: someone whose LDL rises much more than most people’s when they eat more saturated fat. The article’s advice for that person is concrete: change the fats, adjust the diet, or rethink keto. Without the before-and-after tests, neither person would know which one they are.

The Open Question

All that fat and your heart — still unsettled.

The evidence on keto and heart health points both ways. A lot depends on how your own body responds.

The American Heart Association, the U.S. Dietary Guidelines and Harvard’s Nutrition Source stand for the careful, mainstream view. They warn that saturated fat can raise LDL cholesterol, especially in “hyper-responders.” The American Heart Association says keto “doesn’t meet standards for a healthy diet.” Long-term proof that it helps is still scarce.

The article adds a note about that advice. The newest U.S. Dietary Guidelines came out in January 2026, and they dropped the old food pyramid. The food pyramid was the old government chart that put bread, cereal, rice and pasta at the bottom as the biggest part of the diet. The new advice tells people to cut refined carbs, like white bread and sugar, and to eat real food, including protein and full-fat foods. But it kept the old limit on saturated fat: no more than 10% of your daily calories. So official advice has moved partway toward keto, but not on fat. The article treats that advice as one input, not the verdict. The verdict is your own blood work.

Keto supporters and some recent reviews point to a different result. Keto often lowers triglycerides and can improve other signs of how the body handles fuel. LDL response also varies enormously from person to person. From that side, saying “it harms hearts” is too broad.

The two sides do not carry the same official weight. The caution comes from the big groups that write diet advice. The other side comes mainly from keto-friendly cardiologists, who are heart doctors, and from practitioners and supporters. They believe general advice misses important differences between people.

You can keep keto’s possible benefits and choose your fats more carefully. Choose olive oil, avocado, nuts and fish. Use less butter, coconut oil, fatty processed meat and other rich sources of saturated fat.

Get blood work before you start, then again after a few months, with your doctor. Track LDL and triglycerides. If LDL rises sharply, you may be a hyper-responder. Change the fats, adjust the diet, or rethink keto.

💡 Before you read this part

Below are six steps that pull the whole article together. Step one: real food; if you eat a package labeled keto, read the carb count. Step two: water and salt from the first day, and ease in over a week. Step three: if you take diabetes or blood-pressure medicine, have kidney or liver disease, or are pregnant, ask your doctor first; the article even gives you the exact question to ask. Step four: blood work before you start and after a few months, especially LDL. Step five: judge every health claim, including this one, by what it does for you. Step six: what to say when someone tells you keto is dangerous, or that it cures everything.

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Why does medicine need a check first? A medicine dose is set for the body you had when the doctor wrote the prescription. Diabetes medicines push blood sugar down, and blood-pressure medicines push blood pressure down. Keto can push both of those down too. Put the medicine and the diet together and a number can go lower than it should. So the doctor may need to change the dose. For a healthy adult who takes neither kind of medicine, that problem does not come up, which is why Step 3 is only for some people.

The Checklist

How to actually try this — safely, and on your terms.

Step 1. Build meals from eggs, fish, meat, olive oil, avocado, nuts and low-starch vegetables. Dr. Berry’s strict rule is to skip packaged food labeled “keto”. If you do use one, read the carb count and judge it by your own results. Choosing olive oil, avocado and fatty fish may also ease worries about your heart.

Step 2. From day one, drink water and replace salt and minerals. Ease in over a week instead of cutting carbohydrates to zero overnight. That keeps the rough first week small.

Step 3. If you take diabetes or blood-pressure medicine, have kidney or liver disease, or are pregnant, ask your doctor: “I want to try low-carb/keto — do we need to adjust my medication first?” A healthy adult without those conditions can start without that medicine check.

Step 4. Get blood work before you start and again after a few months, especially LDL and the other cholesterol numbers. The results show whether keto is helping your health without moving LDL the wrong way.

Step 5. Judge every health claim, including this article, by what it does for you, and check anything that sounds too big. The site’s fact-check tool copies the prompt for you in one click. Paste in the claim and it does the rest.

Step 6. When someone says “keto’s dangerous!” or “keto cures everything!”, point them to the section on ketosis and ketoacidosis. Send them this article with one rule: do not take anyone’s word for it; check the sources.

💡 Before you read this part

Below are keto’s two strongest results, the ones measured in real studies. First, epilepsy. Up to one in three people with epilepsy have seizures that medicine cannot stop. A review that pulled together 11 studies of children like that found that about 56% of them had their seizures cut by more than half, and about 16% stopped having seizures. Second, type 2 diabetes. Dr. Sarah Hallberg led a two-year trial that compared a keto program with usual care. More than half of the people on keto reached remission, which means the signs of the disease went away for now. About nine in ten of those who used insulin cut back or stopped. The section ends by saying these results are not a promise for everyone.

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Put the epilepsy numbers into children. Picture 100 children whose seizures medicine cannot control. Those are the hard cases, the children who had run out of options. Now put those 100 children on the ketogenic diet. About 56 of them see their seizures cut by more than half. About 16 stop having seizures.

The Receipts

The oldest, best-proven win — with dates and receipts.

Keto’s oldest proven use began about a century ago in hospitals. Up to one in three people with epilepsy have seizures that medicine cannot control.

In those hard cases, a systematic review found that about 56% of children cut their seizures by more than half. About 16% became seizure-free.

The evidence for type 2 diabetes is newer. Dr. Sarah Hallberg, a Doctor of Osteopathic Medicine with a master’s degree, served as medical director of Medically Supervised Weight Loss at Indiana University Health and at Virta Health.

She led a large controlled trial, checked by other scientists before it was published. It compared a very-low-carbohydrate ketogenic program with usual care.

After two years, more than half of the people on the ketogenic program were in diabetes remission. Of those who had been using insulin, about nine in ten cut back or stopped it.

These results do not promise that keto will work as well for everyone. They show why it belongs in serious medical conversations. Its strongest proof is a century of treating childhood epilepsy and a controlled two-year diabetes trial.

💡 Before you read this part

Below, the article tells you how to check it. It names its neutral sources, the ones with nothing riding on whether you try keto: the Epilepsy Foundation, Johns Hopkins, the National Institutes of Health, Harvard, the American Heart Association and a nurses’ group for heart care. It reminds you that every person quoted was labeled, as a physician, a chiropractor or a fitness teacher, because they do not carry equal weight. And it ends with one rule about your own blood work.

↓ the section it explains is right below

The Rule

Don’t take anyone’s word for it.

Every claim in the article comes from a named source. The neutral ones are the Epilepsy Foundation, Johns Hopkins Epilepsy Center, the National Institutes of Health’s PubMed and StatPearls, Harvard, the American Heart Association, and the Preventive Cardiovascular Nurses Association.

The National Institutes of Health is the U.S. government’s health research agency. PubMed is its free library of medical research, and StatPearls is a set of medical reference articles.

One rule about the voices you heard. Physicians, chiropractors and fitness teachers do not carry equal weight, and each one was labeled where they spoke. Believable experience stays in, clearly marked. Nobody’s opinion outranks measured results, including the article’s own.

The one thing to take with you: your own blood work beats every opinion on this page. Test before, test after, and follow your numbers.

Every source, with its link

Johns Hopkins Epilepsy Center — neutral anchor, primary institution: Dr. Russell Wilder at the Mayo Clinic, 1921, and the coining of “ketogenic diet.”
NIH/PMC — “Ketogenic diet: old treatment, new beginning” — peer-reviewed review: the diet’s origin and its century of continuous clinical use.
Epilepsy Foundation — neutral anchor, professional body: the classic diet “prescribed by a physician and carefully monitored by a dietitian” with a short hospital stay, and its seizure figures (over half of children who go on the diet see seizures cut by at least half; usually 10–15% become seizure-free).
International Ketogenic Diet Study Group, via NIH/PMC — clinical management recommendations for the diet in epilepsy.
Lefevre & Aronson, Pediatrics, 2000, via PubMed — systematic review of 11 studies in children whose seizures medicine could not control: about 56% cut seizures by more than half; 16% became seizure-free.
Child Neurology Foundation — drug-resistant epilepsy — up to 1 in 3 people with epilepsy keep having seizures despite medication.
StatPearls, NCBI/NIH — neutral anchor: evidence-based indications, clinical applications, and the keto-flu mechanism.
Frontiers in Medicine, 2024 — narrative review of keto in clinical populations; where each use sits on the evidence ladder.
Preventive Cardiovascular Nurses Association — professional body, neutral anchor: ketosis versus ketoacidosis, and insulin as the brake.
Diabetes.co.uk — nutritional ketosis at roughly 0.5–3 mmol/L against DKA at roughly 15–25 mmol/L.
ZOE — an independent third source for the same two ranges.
Healthline — keto flu: sodium and water loss, the water released with glycogen, and the salt-and-minerals fix.
Harvard Nutrition Source — consensus anchor carrying the Harvard and American Heart Association caution: saturated fat, LDL, “hyper-responders,” thin long-term evidence; also the lower-saturated-fat foods — olive oil, avocado, nuts, fatty fish.
Harvard Health — the caution side of the heart argument, stated at its strongest.
U.S. Department of Health and Human Services, 7 January 2026 — the 2025–2030 Dietary Guidelines: “eat real food,” cut highly processed food and refined carbohydrates. Harvard’s Nutrition Source notes the 10% saturated-fat limit stayed.
Ketogenic diet and cardiovascular risk — state-of-the-art review — review, the variability side: LDL response differs enormously between people.
American Journal of Clinical Nutrition, 2024 — meta-analysis of cardiovascular risk factors on keto, including triglycerides.
American Heart Association — “Here’s how 10 popular diets scored for heart health” — neutral anchor, professional body: the AHA’s own report on its 2023 scientific statement (Gardner et al., Circulation 2023;147:1715–1730), which placed very-low-carbohydrate/ketogenic eating in the bottom tier for being “high in fat without limiting saturated fat,” and no more effective for long-term weight loss than less restrictive diets. The AHA states this as a tier ranking; the article's wording is a summary, not a quote.
Ge et al., BMJ, 2020 — network meta-analysis of 121 randomized trials, 21,942 adults — peer-reviewed review, the twelve-month claim: low-carbohydrate and low-fat diets produced similar weight loss at six months (4.63 v 4.37 kg), and “at 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear.”
“Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks,” Frontiers in Nutrition, 2021 — peer-reviewed review, the adherence half of that claim: “no advantage was seen relative to control diets in studies of longer duration,” and ketogenic diets “have low long-term tolerability, and are not sustainable for many individuals.”
Blundell et al., Diabetes, Obesity and Metabolism, 2017 — the semaglutide crossover study itself: randomized, double-blind, placebo-controlled, two-period crossover; once-weekly semaglutide escalated to 1.0 mg cut total ad libitum energy intake by 24% (−3036 kJ, roughly 725 calories a day) and reduced body weight by 5.0 kg, “predominantly from body fat mass.”
Cipryan et al., Frontiers in Nutrition, 2021 — randomized controlled trial, the low-carbohydrate side of that comparison: over 12 weeks a very-low-carbohydrate high-fat diet, alone or combined with interval training, cut visceral fat, total body fat and trunk fat, while interval training alone did not.
Miller, Villamena and Volek — “Nutritional Ketosis and Mitohormesis,” Journal of Nutrition and Metabolism, 2018 — peer-reviewed review behind the cell-engine claim: nutritional ketosis increases reliance on mitochondrial respiration, and beta-hydroxybutyrate acts as a signaling molecule and not only as fuel. Stated there as potential, not proven.
Kolb et al., “Ketone bodies: from enemy to friend and guardian angel,” BMC Medicine, 2021 — peer-reviewed review behind the autophagy line: ketone metabolism is proposed to trigger an adaptive response that includes improved mitochondrial function and autophagy. A proposed mechanism, not a measured human outcome.
Youm et al., Nature Medicine, 2015 — the lower-inflammation link: the ketone beta-hydroxybutyrate suppresses the NLRP3 inflammasome. Laboratory and animal work, not a human trial.
Danan, Westman, Saslow and Ede — “The Ketogenic Diet for Refractory Mental Illness,” Frontiers in Psychiatry, 2022 — peer-reviewed retrospective case series, not a randomized trial: 31 hospitalized adults with treatment-refractory major depression, bipolar disorder and schizoaffective disorder; depression and psychosis scores improved substantially. This is the metabolic-psychiatry case evidence described in the mental-health section, and Dr. Georgia Ede is a co-author.
NIH/PMC — Hallberg et al. — the two-year type 2 diabetes study itself: peer-reviewed, non-randomized controlled trial; about 55% in remission, about nine in ten insulin users reduced or eliminated insulin.
Virta Health — Dr. Sarah Hallberg’s credential and role: DO, MS; medical director and principal investigator.
Healio — independent reporting of the same two-year outcomes.
Dr. Annette Bosworth, MD — “Dr. Boz” — documenting clinician, observational: excess insulin years before standard blood-sugar tests turn abnormal.
Healthgrades — Bosworth’s credential and practice: board-certified internal medicine.
Doctor Mike, Dr. Mikhail Varshavski, DO — physician, cautious mainstream: the 75/20/5 ratio and “ten times less carbs,” the few days to switch, water weight as “a little misleading,” “the jury’s still out” on healthy brains, and “not super sustainable.”
Talking With Docs — two practicing surgeons: Wilder and “intractable seizures,” ketones the brain draws on “preferentially,” the ketoacidosis warning, and “the research is not totally conclusive.”
Dr. Ken Berry, MD — physician advocate, clinical account: the plate rule and the keto-label rule, leptin and ghrelin, and the changes he watches for in his own patients.
Dr. Eric Berg, DC — chiropractor, not a physician; sells supplements and markets with alarm: “every time you eat you trigger insulin,” kept as a beginner’s picture and his opinion.
Dr. Eric C. Westman, MD, MHS — Duke Health — credential and role: board-certified in internal medicine, Duke University Medical Center, “committed to reversing chronic medical problems through prescription-strength ketogenic diets.”
Dr. Eric Westman — “Study Compared Ozempic To the Keto Diet! Which is Better For Losing Weight?” — practitioner account, the source of every Westman line in this article: “they ate less,” “it became a low calorie diet even though you didn’t have to tell people to eat fewer calories,” “hunger goes down on a shot. Hunger goes down on a keto diet,” and the dirty-fishbowl image, which he credits to the Means. The side-by-side reading of the drug study and the low-carbohydrate study is his own; as he says in the video, no randomized trial has yet pitted a keto diet directly against a GLP-1.
Dr. Westman Reacts: Insulin Resistance on Keto — practitioner account: why low insulin on a keto diet is not the pathologic insulin resistance the same test would signal on a high-carbohydrate diet.
Metabolic Mind — “Is Keto Linked to Insulin Resistance? What the Research Says” — practitioner account, Dr. Bret Scher on camera: the 75-gram oral glucose tolerance test, the terms “adaptive glucose sparing” and “physiologic insulin resistance,” and the normalization once carbohydrate is ramped back up over three days to two weeks.
Dr. Bret Scher, MD — Metabolic Mind — credential and role: board-certified cardiologist and lipidologist, Medical Director of Metabolic Mind, a non-profit initiative of the Baszucki Group.
Dr. Georgia Ede, MD — credential: Harvard-trained, board-certified psychiatrist working in nutritional and metabolic psychiatry, whose stated subject is “the inner workings of the brain and its metabolism.” Her position here is an attributed clinical view in an emerging field, not consensus.
Thomas DeLauer — “The New Era of Keto in 2026 (NEW science, NEW rules)” — fitness educator, practitioner framing rather than clinical consensus: protein first with fat as fuel, do not chase the highest ketone reading, metabolic flexibility over being anti-carb, and about eight weeks before judging it.
Casey and Calley Means — who the fishbowl image comes from: Casey Means holds an MD; Calley Means holds a BA and an MBA and is not a physician. They co-wrote Good Energy (2024). The image reaches this article second-hand, through Westman.