Refuting The Idea That Humans Must Be Herbivores Because Only Herbivores Get Atherosclerosis

I thought I’d do an article on this subject because the second link that pops up when you Google “only herbivores get atherosclerosis” is this absolutely garbage refutation on the subject.

This article comes to us from an author who calls himself Barry Groves PhD, published in January of 2012, on a blog called Second Opinions.  Dr. Groves seems to think the entire medical establishment has misunderstood the cause of heart disease as being caused by saturated fat and cholesterol.  Rather, he claims it’s caused by sugar and carbohydrates.

The article starts out by citing a 2008 editorial “The Cause of Atherosclerosis”, published in the journal Nutrition in Clinical Practice by cardiologist William C. Roberts MD.  In that article, Roberts makes the statement that only herbivores can develop atherosclerosis from ingesting cholesterol and saturated fat.  It should be noted that Roberts is an eminent cardiologist with over a thousand published papers.  It should also be noted that nothing Groves says in his entire article refutes this statement by Roberts.

Roberts states:

Atherosclerosis is easily produced in nonhuman herbivores (eg, rabbits, monkeys) by feeding them a high cholesterol (eg, egg yolks) or high saturated fat (eg, animal fat) diet… And atherosclerosis was not produced in a minority of rats fed these diets, it was produced in 100% of the animals! Indeed, atherosclerosis is one of the easiest diseases to produce experimentally, but the experimental animal must be an herbivore. It is not possible to produce atherosclerosis in a carnivore…”

It is virtually impossible, for example, to produce atherosclerosis in a dog even when 100 grams of cholesterol and 120 grams of butter fat are added to its meat ration. (This amount of cholesterol is approximately 200 times the average amount that human beings in the USA eat each day!). (The American Journal of Cardiology, 1990, vol. 66,896.)

After citing this article, Groves then goes on to make some pretty bold claims:

-The first fact is that herbivores do not have to be fed cholesterol-rich foods for them to develop atherosclerosis. Merely feeding them the wrong, usually starch- and sugar-rich, plant foods can cause cardiovascular disese (sic).

-The second fact is that carnivores not only can develop atherosclerosis, they do — if they are fed carbohydrate-rich plant foods.

-And the third fact is that levels of blood cholesterol over 150 do not cause or increase the risk of heart disease or atherosclerosis.

To back up these rather outrageous claims, Groves cites a total of 13 articles.  Who knew the entire basis for atherosclerosis could be overturned within one blog post citing only 13 articles! A close look at the studies he cites to back his rather absurd claims might help us illuminate his nonsense.

So let’s go down his arguments point by point.

Dr Roberts is entirely correct when he says that only herbivores develop atherosclerosis — in laboratory conditions when the object of the exercise is to produce atherosclerosis and they are fed an inappropriate cholesterol and animal-fat diet. But that is not because cholesterol and animal fats are intrinsically harmful substances, but because they are inappropriate and alien in the diet of a herbivore.

I agree with that statement.

Gorillas and other herbivorous primates in the wild and eating their natural diet never develop atherosclerosis. But captive animals are not fed what they would normally eatin the wild.. Dr Cousins, writing is 1976, tells us that “It is clear that most zoos feed their gorillas a principally frugivorous diet, while the diets of wild gorilla populations are undoubtedly basically herbivorous.”1 Feeding a gorilla, for example on a high-starch, low fibre diet which, for a hindgut digester that breaks down dietary fibre to produce short-chain fatty acids, equates to a low-fat diet, they do suffer premature cardiovascular disease. And without any cholesterol or animal fat in their diets.2,3

I agree, gorillas are not starchivores or frugivores, so feeding them an incorrect diet can result in an overproduction of cholesterol and cardiovascular disease.

The same is true of carnivores. Dogs, cats, lions, etc, don’t develop atherosclerosis when fed a cholesterol-rich diet simply because that is appropriate for them. But they suffer these conditions if fed starchy plants. Any vet can confirm that carnivorous pets and zoo animals develop atherosclerosis if fed plant- and grain-based pet food. In fact, heart attacks are almost as common in pet dogs as they are in their owners.4,5

Feeding incorrect diets to carnivores such as dogs and cats can result in them getting atherosclerosis.  However, the development of atherosclerosis is almost always secondary to an inflammatory disease. So far, it seems we’ve established that when you feed an animal a diet that is not appropriate for it, it can result in cardiovascular disease.  It’s worth noting that the vast majority of atherosclerosis in dogs is related to hypothyroidism and diabetes.  Saturated fat and cholesterol have no effect on atherosclerosis in carnivores.  These facts seem to support my position, not Groves.  It seems strange he would even mention this.

The same is true of animals kept in captivity in zoos. Dr. Clarke Stout pointed out in 1969 that:

“the arterial lesions of animals are often quite similar to the early human proliferative atherosclerotic lesions. Since the arteries of most mammalian species (including man) resemble each other morphologically, it seems reasonable to assume that the finding of similar arterial lesions in different species might imply that similar pathogenic mechanisms had been operative in their production.”

I have no problem with that statement either.

And it seems that the cause of the lesions is the same as in both us and our pets: starchy carbohydrate foods.

“Food thrown by the public was available to the large Carmivora and the seals and sea lions. Although the latter received primarily fish from public food dispensers installed for that purpose, the large Carnivora, and particularly the bears, were offered a variety of tidbits including peanuts, popcorn, candy, and other items.”6

So, we now know that atherosclerosis can and does also affect carnivores. This fact destroys Dr Roberts’ assertion that humans must be herbivores.


Whoa!  Hold on there buddy!  How the hell did you arrive at that conclusion?  So because some carnivores are known to develop atherosclerosis from eating starches, and because some herbivores fed saturated fats mixed with starches can develop atherosclerosis, you jump to the conclusion that human atherosclerosis is caused by starches?   WTF?  Does anyone else see a problem with his logic here?

Groves completely ignores the fact that when people are fed a whole food starch based vegan diet, their cholesterol numbers and arterial function dramatically improve.  Those same studies also show that when people are fed cholesterol and saturated fats, their cholesterol numbers and arterial function are dramatically impaired.

So based on those studies, wouldn’t it be obvious to conclude that humans are not omnivores, herbivores or carnivores, but rather starchivores?  I mean, we’ve already established that when you feed an animal a diet that is inappropriate for it, it can develop cardiovascular disease.  Thus, doesn’t the bulk of Grove’s article support the assertion that humans are starchivores?

Every large population study and every medical ward study, that has analyzed the data in terms of a low fat vegan diet (which most do not), has found vegans have the lowest all-cause mortality, the lowest over-all incidence rate of cancer, the lowest incidence of heart disease, the lowest incidence of diabetes and the lowest incidence rates of obesity!

Groves then goes on to cite a 2011 study on cholesterol that he claims supports his position.

Although we have been taught for some decades that rising cholesterol levels increase the risk of atherosclerosis and a heart attack, there is very little actual evidence to support this hypothesis.

“The cholesterol hypothesis links cholesterol intake and blood levels to cardiovascular disease. It has had enormous impact on health care and society during decades, but has little or no scientific backing that is relevant for the human species.”So began a paper published in 2011.8

It pointed out that “The idea that cholesterol is dangerous took root with the well-known Framingham study9. It was found that the cholesterol level had been slightly increased after a heart attack in previously healthy men. Therefore, it was claimed that high cholesterol was a risk factor for myocardial infarction. Amazingly, very little attention was taken when the 30 years follow-up of the Framingham project was published 10. It turned out that high cholesterol was not a risk factor for men older than 47 years and not for women at all. Further, it was found that more men had died of a heart attack among those whose cholesterol had decreased over the years. The authors wrote :

“For every milligram percent cholesterol had decreased, cardiovascular mortality and total mortality increased by fourteen and eleven percent” .

First off, keep in mind this one study goes against the results of thousands of studies that reach completely opposite conclusions.  Perhaps this fact might be a clue that there is something fishy about this study?

The problem stems from what the authors consider “high” cholesterol to be.  You see, the terms “high” and “low” are arbitrary.  They are not based on objective scientific values.  For example, US dietary guidelines consider a “normal” total cholesterol level to be below 200 mg/dL.  However, as the study above shows, people who are within this so-called “normal” range frequently drop dead of heart attacks.

If you start with a high cholesterol level, and then reduce that down to levels that are still in the red zone, you’re still in the red zone!  In fact, evidence suggests that mixing carbs and meat is the worst thing you can do!  So it makes sense that people who slightly reduce their cholesterol by adding in more carbs to their diet put themselves at even greater risk for heart disease if they continue to eat those carbs with meat.

The real “normal” cholesterol level for a human is below 150 mg/dL.  We know from large population studies that when people have a total cholesterol level below 150, heart disease is virtually unheard of.  According to one survey taken in rural Africa during the 40s, out of over a thousand autopsied deaths, none were from a heart attack because everyone essentially ate a vegan diet in that region!  Heart diease was unheard of in rural Africa during the 40s because no one could afford to eat meat!  Even using recent statistics, the average total cholesterol level of native Africans has been measured to be 139, compared to 212 for Americans, with correspondingly much lower rates of cardiovascular disease.

Groves goes on to cite a few more studies that make the same errors as the study above.  The other studies cited never consider vegan diets as a separate category and only look at cholesterol level trends from a subjective baseline.  Unscrupulous scientists use this same statistical trickery when doing comparative studies on fat intake.  I did an article that covers several of these junk studies in more detail here.

Finally, Groves concludes his arguments with this statement:

There are many human cultures around the world from the poles to the tropics that live entirely on animals, eat a high cholesterol, high animal-fat diet, but don’t suffer heart attacks. There are others whose traditional diets are a mix of animal- and plant-sourced diets who also do not have heart attacks. It is only we who eat processed foods — which are predominantly based on cereals and processed vegetable oils who do. This strongly suggests that the inappropriate part of our diet is not the animal-sourced foods but the processed parts. And they are all from the cheap-to-produce plant world. It is the same with our carnivorous pets and captive carnivorous animals in zoos.

And that destroys Dr Roberts last argument.


If Groves had done his homework, he would know that, in those societies where they survive primarily on meat or dairy, the meat and dairy is highly fermented.  The fermentation of the food causes the meat and dairy to breakdown into carbohydrates. See these articles on the Massai and Inuit tribes for more information on this subject.  Further, when the Massai were actually autopsied for evidence of heart disease, researchers found evidence of extensive atherosclerosis.

A few final points worth noting.  When was the last time you saw a lion carve off a hunk of gazelle meat, roast it on a spit over an open fire and then cover it in excessive amounts of salt to make it palatable?  Omnivores and carnivores have taste receptors for raw meaty amino acids.  Raw meat to a lion tastes like a cupcake to a human.

Real omnivores and carnivores also have teeth designed for ripping flesh from bone.  Their jaws only move up and down, not side to side.  Omnivores and carnivores rip and gulp, they don’t grind their food with molars.

Carnivores also don’t have much amylase in their saliva. Amylase is an enzyme that breaks down starchy foods.  Humans have abundant amounts of amylase in their saliva and the human body is predisposed to use carbohydrates as its preferred fuel source, passing up proteins and fats if carbs are available. Humans possess six salivary amylase genes, while other primates just have two, increasing the ability to digest starch.

The consensus among anthropologists today is that the human brain was able to evolve to such a large size because of increased carbohydrate consumption.  The human brain runs almost entirely on glucose, and is the most energy intensive organ in the human body.  The discovery of fire for cooking allowed early humans access the energy in starchy root vegetables that would otherwise have been too dense to consume in their raw form.

While early humans certainly ate meat, the vast bulk of their diet came from starchy root vegetables.  No hunter gathering tribal society alive today eats a diet of predominately meat.  Most tribal societies today eat meat only occasionally, and are incapable of hunting enough meat to eat it on any kind of consistent basis.

If you want some real science on the subject of nutrition, I suggest watching the latest annual state of nutrition lecture given by Dr. Michael Greger.  Also, here’s an article written by Dr. Roberts on this very subject, published in the Proceedings of the Baylor University. Medical Center.


  • Uncle Siam

    Great article! Thank you very much. I was worried at first that you might side with Carnism. I learned a few things to boot!

  • Tayla Morris

    Thanks for taking the time to write this!

  • It should also be noted that nothing Groves says in his entire article refutes this statement by Roberts.