More Defending of The Indefensible Ketogenic Diet

Michael Carrato, one of my readers, didn’t like what I had to say about his ketogenic diet regimen.  Carrato writes:

Are you saying that a ketogenic diet CANNOT reverse diabetes and improve markers for CHD? Because it seems that the position of the anti-fat crowd is that keto is positively incompatible with good health, that low fat is the only pathway to curing metabolic illness. Peter Attia and Gary Taubes have challenged that dogma and produced plenty of evidence that the case against fat has NOT BEEN PROVEN sufficiently. In fact, for many people, low carb has been literally a life saver. Count me among them, BTW, so you can fully assess my bias.

I’ve discussed the absolutely massive amount of flaws in Peter Attia’s and Gary Taubes’ lectures here.

Ketogenic diets may improve biomarkers for diabetes and heart disease in people who have been eating the standard American diet due to the weight loss they induce. However, some people will be genetically disposed to have worsening atherosclerosis when on a high fat diet, even with associated weight loss and improved blood lipids.

Long term prospective studies done on children who are placed on a ketogenic diet for the treatment of epilepsy show a wide range of side effects, with the most common two being gastrointestinal disturbances (40.6%) and hyperlipidemia (12.8%).

Studies on children and adults have shown increased arterial stiffness on ketogenic diets.  Saturated fat has been directly observed to cause inflammation, as well as impair endothelial function.  A high saturated fat meal also leads to an acute post-meal increase in circulating endotoxins, which is especially terrible for diabetics. So even though ketogenic diets tend to improve lipid profiles, the diet can still damage the arteries.

There have been no prospective studies using coronary artery calcium scans showing that a ketogenic diet can reverse heart disease the way a low fat whole food plant based diet can.  If you follow a ketogenic diet, I highly recommend you get regular coronary calcium scans to ensure you don’t have progressing arterial disease.

Further, there are no long term studies that compare cardiovascular incidents between groups of vegans and people on long term ketogenic diets.  While some studies have shown improvement in biomarkers for people on ketogenic diets, that doesn’t mean they are as good as a vegan diet when it comes to lowering disease risk long term.

When vegans are compared to healthy meat eaters who eat small portions of meat compared to the average population, the vegans have significantly lower rates of cancer, diabetes and heart disease; this was proven in the AHS2 study.

We also know that meat, in particular processed meat, is a known carcinogen.   The current evidence for the carcinogenicity of processed meat places it in the same category of evidence as cigarettes. Animal protein is known to increase IGF-1, a cancer promoting hormone.  When we compare meat eaters to vegans and vegetarians, the vegans have the lowest levels of IGF-1.   We also know that cooked meats produce heterocyclic amines, which are also a known carcinogen.

So I’ve just linked several studies showing how a ketogenic diet, high in saturated fat, can impair endothelial function, stiffen the arteries, increase inflammation and promote cancer growth.  I’m sure you will ignore these as minor side-effects that can be dismissed though – because what matters to you most is not being fat while getting to consume a mountain of dead bodies – right?

We know that when people are put on an ad libitum (eat as much as you want) whole food vegan diet, they show improvements in diabetes and cardiovascular disease risk.  They also show a reversal of cancer and heart disease as well.  So here we have proven randomized control trial data, some of the strongest evidence available, showing us that a whole food low fat plant based diet can reverse heart disease and some forms of cancer.

So getting back to your point, the keto diet can indeed improve biomarkers for CVD and diabetes, and I’d say it’s certainly healthier than eating the standard American diet, but that doesn’t mean it is healthy.

Carrato goes on to say,

If, perhaps, Attia were saying something to the effect that “low carb is the ONLY diet for anyone”, then certainly I would be lining up against him too — though perhaps without the immature ad hominems. But he’s NOT saying that, and the low fat people ARE saying it. He is expressing reasonable opposition to what has been such a dogmatic view that it is encoded in national policy and taught to our children!

Attia is promoting a diet that will end up getting some people killed.  Granted, most people would probably have their health improve by switching to a ketogenic diet, but only if they are currently eating a standard American diet.  Do you think it would be reasonable for Attia to tell a whole food vegan to ditch their diet and start eating nothing but dead bodies, cruciferous vegetables and high fat foods?

The data shows us that there will always be a subset of people who will end up having a heart attack or contracting cancer strictly because they were following a meat based ketogenic diet.  To me, this is not a reasonable position to advocate for when we know that a low fat whole food plant based diet can achieve better outcomes.  Doctors should be promoting the best diet, not a second or third best diet.

Admittedly, I am not a libertarian, but I am quite familiar with libertarianism, and your post seems to be 180 degrees diametrically opposed to what your chosen ideology professes. Shouldn’t the evidence be presented from all sides so that people are free to use their own judgement to come to an informed decision on what is best for them?

Libertarianism deals with politics, so I’m not sure what libertarianism has to do with diet advice.  I’m a libertarian because reason and evidence demonstrate free markets are the best means of improving the human condition.  Likewise, I promote a low fat high carb whole food plant based diet because evidence clearly demonstrates this is the ideal diet for humans to consume.

Further, not only is the vegan diet the best for humanity in terms of health, it is undeniably better for the environment, better in terms of efficiency (more human food produced per acre), and clearly has less ethical cognitive dissonance (why not kill and eat dogs?).

So yeah, smart people who think logically eat vegan.  That’s probably why vegetarians have IQ scores that are 10 points higher than meat eaters.


  • David Brown

    I hesitate to respond. It is clear from your tone and willingness to smear Peter Attia publically as well as your assessment of the literature that you have a rigid agenda. But because some people may believe your take on things, I will respond.

    First off- there are many very-well controlled interventional studies that have compared the very low carbohydrate and/or ketogenic diets with other types of diets including low-fat, higher carb diets. One of the best was the A to Z trial from the Stanford group. This study showed that the low-carb diet was superior to other diets including low-fat, high carb diet in weight loss and cardiac biomarkers. The better controlled the study is, the more clear this relationship is demonstrated. The studies that are best controlled show the most significant benefit to a very low carb diet.

    Second, your claim about high-fat diets effect on arterial reactivity is flawed. The study you cited is based on a three day diet log- pretty flimsy study. A far more better controlled study measures saRHI at baseline and after three weeks of dietary intervention- a far superior study design. And this showed that a very low carb diet improved small arterial reactive hyperemia in obese patients. The link is here:

    Consistent throughout your article here is cherry-picking the studies that support your claims. And you ignore studies with far superior design and outcomes that are contrary to your claims. Why?

    You cite other bad studies. The articles on dietary fats causing inflammation and impairing endolethial cell function are studies done with mice. Do you know that the food sources in many of those studies have high levels of carbs in addition to high fat? Important point. But there are far better studies in humans that show that saturated fats do not cause any impairment in endothelial cell function and arterial stiffness. The link is here:

    And you claim that there are studies that show a decrease in coronary calcification with a low-fat planet based diet. Can you direct me to those studies?

    You also claim that a plant based diet improves metabolic markers of cardiac risk. Studies show very consistently that a plant based diet has little effect on triglycerides and actually lowers HDL- the good cholesterol. These two markers are really the most important markers on a routine cholesterol panel. Vegan folks love to tout the effect on cholesterol of a plant based diet, but this only shows that you do not understand cholesterol. LDL-C cholesterol is a poor marker for cardiac risk. In fact, a huge study of 136,000 cardiac admissions revealed that the majority of those cardiac patients being admitted with cardiac events had LDL levels in the desirable range. LDL is a particle of which there are many varieties in size and density. The particle number is far better at predicting cardiac events that just a generic LDL-C level. And guess what. As the percentage of calories from carbohydrates increases in a person’s diet, the greater the increase in LDL particle number, and hence the cardiac risk. So you really cannot claim that a plant based diet improves cholesterol markers of cardiac risk.

    As far as diabetes, a low carb, high fat diet is far superior to a plant based, high-carbohydrate diet for diabetes. Not even close. While the studies demonstrating an improvement in Hgb A1C with a plant based diet, those improvements pale in comparison to the improvements patients see on a very-low carb, high fat diet.

    I suggest you include more studies in your analysis. It is clear that you are biased and are really just looking to justify your position and opinion. And you are too willing to call decent, honest researchers liars. Good day.

  • hws

    This was my favorite part – “Attia is promoting a diet that will end up getting some people killed.” Too good in the context of diet discussion and even better knowing it’s coming from a plant based diet advocate.