Keto Diet Debunked: the Dangers Revealed

Page Summary: quotes & links to reports in science journals and by doctors and other health professionals that debunk and refute the claims made for the keto or ketogenic diet; that reveal the grave dangers of higher rates of disease and death.

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From a Journal of the American Medical Association report on Keto: “the diet’s potential risks are real.” Meta-analysis condemns the dangerous and unsubstantiated Keto diet.

Excerpts: “The ketogenic diet has recently received much attention for its promise of treating obesity and type 2 diabetes. However, the enthusiasm for its potential benefits exceeds the current evidence supporting its use for these conditions …

Is the ketogenic diet more effective for weight loss than other diets? In a meta-analysis of 13 studies lasting longer than a year, researchers found that the ketogenic diet was associated with less than a kilogram of additional weight loss over high-carbohydrate, low-fat strategies … Furthermore, a meta-analysis of 32 controlled feeding studies found that energy expenditure and fat loss were greater with low-fat diets compared with ketogenic diets

Any diet that results in weight loss does so because it reduces calorie intake. The ketogenic diet, when used for weight loss, is no different. The salient questions are whether it is sustainable and whether it promotes long-term health. No studies, to our knowledge, have evaluated ketogenic diets for cardiovascular events or mortality, although observational studies in the broader low-carbohydrate diet literature suggest INCREASED ALL-CAUSE MORTALITY …”

“What about the role of a ketogenic diet in the treatment of type 2 diabetes? … A meta-analysis of randomized long-term studies comparing the ketogenic diet with low-fat diets for weight loss reported no difference in glycemic control among persons with type 2 diabetes

there is little if any evidence that ketogenic diets specifically improve carbohydrate intolerance independent of weight loss, unlike other dietary approaches in which glycemic control is improved despite the consumption of healthful carbohydrate-rich foods, such as legumes, whole grains, and fruits, even in the absence of weight loss …

A review of the literature on ketogenic diets for the treatment of pediatric epilepsy reveals multiple adverse effects, ranging from the relatively benign but inconvenient “keto flu,” an induction period of fatigue, weakness, and gastrointestinal disturbances, to the less common but deadlier occurrence of cardiac arrhythmias from selenium deficiency. Other documented adverse effects include nephrolithiasis, constipation, halitosis, muscle cramps, headaches, diarrhea, restricted growth, bone fractures, pancreatitis, and multiple vitamin and mineral deficiencies …

The greatest risk, however, of the ketogenic diet may be the one most overlooked: the opportunity cost of not eating high-fiber, unrefined carbohydrates. Whole grains, fruits, and legumes are some of the most health-promoting foods on the planet. They are not responsible for the epidemics of type 2 diabetes or obesity, and their avoidance may do harm. In a systematic review and meta-analysis of 45 prospective studies, researchers found that whole grain intake was associated with a dose-dependent reduction in risk of coronary heart disease, cardiovascular disease, total cancer, and all-cause mortality.

Similar findings have been seen with fruits and legumes. Nearly all experts agree that highly processed, refined carbohydrate-rich foods should be avoided. Blurring the distinction between refined and unrefined carbohydrates and thus excluding both precludes the numerous health benefits of unrefined carbohydrates
some of the longest-living populations, the so-called Blue Zone communities (eg, Greece, Japan), subsist on a carbohydrate fare that exceeds 50% of daily calories

Although the ketogenic diet has garnered much attention for the dietary treatment of chronic diseases such as obesity and type 2 diabetes, the evidence supporting its use is currently limited and the diet’s potential risks are real. Physicians and patients should continue to judiciously appraise the benefits and risks of the ketogenic diet in accordance with the evidence, not the hype.”

Reference: “The Ketogenic Diet for Obesity and Diabetes—Enthusiasm Outpaces Evidence”, JAMA Intern Med. Published online July 15, 2019;

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The Lancet 2018: “Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality [meaning more deaths], whereas those that favoured plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality” [meaning less death and longer lifespans]
“We studied 15,428 adults aged 45–64 years, in four US communities …”
Reference: “Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis”, The Lancet, Volume 3, issue 9, September 01, 2018;

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Dr Joel Kahn: “Doctor Debunks Keto Diet” at

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From a 2018 report in Canadian Family Physician, on ketogenic diets: “Adverse effects are common, including constipation (33%), halitosis (30%), muscle cramps (28%) … headache, diarrhea, weakness, and rash …”
Regards weight loss: “higher-quality studies show no difference. Weight loss peaks at about 5 months but is often not sustained …”
Regards higher death rates: “low carbohydrate intake might be associated with increased mortality.
Reference: “Ketogenic diet for weight loss”, Canadian Family Physician December 2018, 64 (12) 906;

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Dr Greger MD “Keto Diet Results for Weight Loss – Ketogenic diets and the $33-billion diet gimmick.”

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Excerpts: “The carbohydrate-insulin model of obesity, the underlying theory that ketogenic diets have some sort of metabolic advantage, has been experimentally falsified. The keto diet’s proponents’ own studies showed the exact opposite: ketogenic diets actually put you at a metabolic disadvantage and slow the loss of body fat. How much does fat loss slow down on a low-carb diet?
If you cut about 800 calories a day of carbohydrates from your diet, you lose 53 grams of body fat a day, but if you cut the same number of fat calories, you lose 89 grams a day. Same number of calories, but nine pats of butter worth of extra fat melting off your body every day on a low-fat diet, compared to a low-carb diet. Same number of calories, but about 80 percent more fat loss when you cut down on fat instead of carbs … The title of the study speaks for itself: “Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity.” [1] …
The low-carb group was losing mostly lean mass—water and protein. This loss of water weight helps explain why low-carb diets have been “such ‘cash cows’ for publishers” over the last 150 years. That’s their secret. As one weight loss expert noted, “Rapid water loss is the $33-billion diet gimmick.” …
The bottom line: keto diets just don’t hold water …
But the thrill of seeing the pounds come off so quickly on the scale keeps many coming back. When the diet fails, the dieters often blame themselves. But the intoxication of that initial rapid weight loss may tempt them back, like getting drunk again after forgetting how terrible the last hangover was. This has been dubbed “the false hope syndrome.” The diet industry thrives off of “repeat customers,” something low-carb diets were built for, given that rapid initial water loss.
But what we care about is body fat. In six days, the low-fat diet extracted a total of 80 percent more fat from the body than the low-carb diet. And it’s not just one study. If you look at all the controlled feeding trials where researchers compared low-carb diets to low-fat diets, swapping the same number of carb calories for fat calories or vice versa … Put all the studies together … and we’re talking 16 grams more daily body fat loss on the low-fat diets. That’s four more pats of butter melting off your body on a daily basis. Less fat in the mouth means less fat on the hips, even taking in the same number of calories.”

Reference: [1] “Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity.” Cell Metabolism, 2015 Sep 1;22(3):427-36;

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In 2018 Dr David L Katz MD debunked the Keto diet craze in an article titled “Ketogenic Leftovers, Reheated- Just for You!

Excerpts: “the ketogenic diet has been with us for nearly 50 years … if there were any merit at all to the implied, magical advantages of the ketogenic diet, there would be lots of thin people living the life and smirking at the rest of us. Instead, obesity rates have only gone up, and markedly, since the Atkins’ heyday of nearly two decades ago …

There is no evidence that the keto diet is superior to any of the dietary variants established to defend against obesity and chronic disease not just in the short term, but over time.[1] In general, direct comparison of low carb to alternatives shows no advantage, even among those genetically predisposed to reveal one.

There are no long-term human studies of the keto diet, and no free-living, healthy human population lives this way. We thus have no evidence that the diet can be maintained, that it fosters health over time, or even that it is safe. Contrast that with the dietary variants of the Blue Zones, known to foster vitality and longevity, generation after generation …

It simply proves that all of the claims of its magical advantages are contrived or confabulated, marketing collateral, not facts. You are, once again, being suckered.

As for athletic performance, there the evidence is rather damning. World-leading researchers in nutrition for optimal human performance have studied degrees of carbohydrate restriction, and found that they tend to compromise peak performance, compound muscle injury, and delay recovery. A prominent colleague in this area recently told me directly that the global community of experts in sports nutrition is uniformly opposed to carbohydrate restriction in general, and the ketogenic diet in particular, based on the data currently available.

And let’s be sure to acknowledge, as the ominous mayhem of climate change is ever less theoretical, ever more up close and personal for us all, that this diet in its standard incarnation is bad for the planet, and if adopted at scale, calamitous …

Most notably, the diet simply isn’t remotely new; it has had the opportunity to impress, delight, and impart its alleged benefits to us for nearly 50 years. Hot concept though it may seem at the moment, the keto diet is the leftovers of yesterday’s fad, renamed, and reheated …”

Source: … David L. Katz, MD, MPH, FACPM, FACP, FACLM is the founding director (1998) of Yale University’s Yale-Griffin Prevention Research Center, Past-President of the American College of Lifestyle Medicine, and Founder/President of the True Health Initiative.

References: [1] “Can We Say What Diet Is Best for Health?”, Annual Review of Public Health, Vol. 35:83-103, March 2014;
Summary excerpt: “The weight of evidence strongly supports a theme of healthful eating while allowing for variations on that theme. A diet of minimally processed foods close to nature, predominantly plants, is decisively associated with health promotion and disease prevention and is consistent with the salient components of seemingly distinct dietary approaches. Efforts to improve public health through diet are forestalled not for want of knowledge about the optimal feeding of Homo sapiens but for distractions associated with exaggerated claims, and our failure to convert what we reliably know into what we routinely do.”

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Leading Cardiologist Dr. Kim Williams, the past President of the American College of Cardiology, says no one should be doing a ketogenic diet:
“from 2007, that’s the first one I saw, large randomized trial, looking at the ketogenic diet and showing that it increased mortality by about 22 percent
then there was one the Journal of the American Heart Association published a few years later that isolated the people who had had a heart attack in the past, the cardiology population that we’re seeing, and they were doing a ketogenic diet. It was a 53 percent increase in mortality.
No one should be doing this [keto diet] …
a meta-analysis, I think they had 13 or 16 trials in it, and average them all out … and the answer was 31 percent increase in mortality. So it’s not something people should do unless your weight loss is more important than your life.”
Source: this video interview titled “ENDING THE KETOGENIC DIET DEBATE” at

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An article by cardiologist Dr. Joel Kahn is titled “The Skeleton in The Ketogenic Diet Closet: What Virta Health, Mark Sisson, Joseph Mercola and Others Leave Out.”

Excerpts: “The skeleton is multiple peer reviewed studies indicating a higher risk of premature DEATH on long term low carbohydrate diets like that recommended by Virta Health. Here is a list of the studies to know about before you shun “carbohydrates” from your diet:

1) Noto et al. This meta-analysis of 272,216 subjects studied for diet and mortality reported that the risk of “all-cause” mortality in those responding that they followed a low-carbohydrate diet was approximately 30% higher than other subjects.

2) Li et al. The Harvard School of Public Health studied over 4,000 men and women who had survived a heart attack. Those eating a lower carbohydrate diet higher in animal protein and fat was associated with a higher risk of all-cause and cardiovascular mortality. This increase was not identified in those responding they ate a plant-based low-carbohydrate diet.

3) Sjogren et al. In an analysis of over 900 elderly Swedish men, a Mediterranean diet pattern reduced mortality while a carbohydrate restricted diet was associated with a 20–40% increase in all-cause and cardiovascular mortality respectively.

4) Fung et al. In an analysis of nearly 130,000 subjects followed by the Harvard School of Public Health, subjects following an animal food based low carbohydrate diet had increase in all-cause, cardiovascular and cancer mortality while there was a reduction in mortality in those following a plant based similar diet pattern.

5) Snell-Bergeon et al. In a series of type 1 diabetics, a higher protein and fat diet was associated with more heart artery calcification, a marker of atherosclerosis, while a higher carbohydrate based diet was associated with a lower burden of artery calcification.

6) Lagiou et al. In a research group of over 42,000 Swedish women, respondents with a dietary pattern of higher protein and low-carbohydrate was associated with higher all-cause and cardiovascular mortality.

7) Trichopolou et al. In a Greek population of nearly 23,000 subjects, those following a low-carbohydrate and higher protein diet had higher all-cause, cardiovascular and cancer mortality.

These 7 studies from various locations and institutions around the world provide a sobering view of adopting a long-term low-carbohydrate diet supported by animal sourced protein and fat calories as is taught by Virta Health and others. The superior outcome with diets based in plant sources is a consistent finding…”


For links to more science reports with findings like those see this site’s page about carbohydrates.

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Dr Greger MD explores “Are Keto Diets Safe? The effects of ketogenic diets on nutrient sufficiency, gut flora, and heart disease risk.”
Excerpts: “Inadequate intake of 17 micronutrients—vitamins and minerals—has been documented in those on strict ketogenic diets … Ketogenic diets tend to be so nutritionally vacuous that one assessment estimated that to get a sufficient daily intake of all essential vitamins and minerals. you’d have to eat more than 37,000 calories a day.
That’s one of the advantages of more plant-based approaches. As the editor-in-chief of the Journal of the American Dietetic Association put it: “What could be more nutrient dense than a vegetarian diet? …
Children have gotten scurvy on ketogenic diets, and some have even died from selenium deficiency (which can cause sudden cardiac death) …
Ketogenic diets have been shown to reduce the richness and diversity of our gut flora. Microbiome changes can be detected “within 24 hours” of switching to a high-fat, low-fiber diet. The lack of fiber starves our good gut bacteria …
If you look at low-carbohydrate diets and all-cause mortality, those who eat lower-carb diets suffer “a significantly higher risk of all-cause mortality,” meaning they live, on average, significantly shorter lives.
From a heart disease perspective, though, it matters if it’s an animal fat or plant fat. Based on the famous Harvard cohorts, eating more of an animal-based low-carb diet was associated with higher death rates from cardiovascular disease—a 50 percent higher risk of dying from a heart attack or stroke—but no such association was found for lower-carb diets based on plant sources.
And it wasn’t just from Harvard. “Low carbohydrate dietary patterns favouring animal…protein and fat, from sources such as [red meat and chicken], were associated with higher mortality; whereas those [favoring] plant protein…and fat…, [from things like] vegetables, nuts, peanut butter, and whole grain[s], were associated with lower mortality…” …
Within three hours of eating a meal high in saturated fat, you can see a significant impairment of artery function. Even with a dozen pounds of weight loss, artery function worsens on a ketogenic diet instead of getting better—which appears to be the case with low-carb diets in general …”

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Dr Michael Greger clip: “Keto Diets: Muscle Growth & Bone Density. Ketogenic diets found to undermine exercise efforts and lead to muscle shrinkage and bone loss.”


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2019 news reports: “High on fat, low on evidence: the problem with the keto diet.
The ultra-low-carb ketogenic diet – which forces the body to burn fat – flies in the face of conventional nutritional advice. It is hugely popular, but is it healthy or sustainable?” at

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2019 reports by Robyn Chuter, ND:

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A 2018 news report is titled: “‘Best diets’ ranking puts keto last, DASH first”.
Excerpts: “If you’re a fan of the “fat-burning” keto diet, you’ll be fired up about its ranking in the 2018 list of best diets from US News and World Report: It’s tied for last, along with the relatively unknown Dukan diet.
Both stress eating a ton of protein and minimal carbs, putting the dieter into “ketosis,” when the body breaks down both ingested and stored body fat into ketones, which it uses as energy. People on such diets often deal with fatigue and light-headedness as they adjust to a lack of carbohydrates”

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A science-based presentation on Youtube: “Diet Debunked: The Ketogenic Diet” at
Summary: “The keto diet has a dark side that only few in the community have the courage to confront and it is all based on the scientific literature.”

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The Magic Pill Debunked – Keto Netflix Documentary
is at
Summary: “A science-based response to the recently released keto documentary that will have you thinking that high meat keto diets cure everything.”

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5 Long-Term Health Risks of Going Keto

7 Dangers of Going Keto: The low-carb, high-fat plan … health experts worry about these side effects and complications.”

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Regards Vegan Keto

Dr Joel Kahn “Vegan Keto: What, Why, Who?” short clip at

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More to come!

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For Further Related Information:

This site also has pages that features quotes and links to a large collection of articles that:

  • Debunk the Paleo Diet
  • Debunk the myths about carbohydrates – many science reports show that higher  consumption of healthy whole-food carbs is associated with less disease and longer lifespan.
  • Debunk protein myths – many science reports show that higher consumption of plant protein is associated with less disease and longer lifespan; while higher consumption of animal protein is associated with higher disease and mortality ie. shorter lifespans.
  • Other pages showcase hundreds of science reports that have discovered the higher rates of disease and death that are associated with consumption of red meat, chicken, eggs, dairy and fish.
  • Another page features excerpts and links to 100+ science reports on the health benefits of plant-based vegan vegetarian diets: lower rates of disease and long healthy lifespans.

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