It is claimed that the vegan diet has strong evidence behind it.
It is said that it can make people lose weight and even reverse killer diseases.
However… vegan proponents usually don’t tell you the full story.
They make it seem like there is overwhelming evidence in favor of the vegan diet.
But in reality, this evidence is weak and there is a large body of evidence that they are ignoring.
The truth is, vegan diets can work… at least for some people.
There are also some ethical and environmental arguments to be made for avoiding animal foods (even though I personally don’t agree with them).
But many vegan advocates are incredibly dishonest about animal foods and spread unscientific fear mongering to convince people that their diet is healthy.
Here are 11 common myths about vegan diets.
1. The Health Benefits of Vegan Diets Are Due to Avoiding Animal Foods
There are a number of studies showing health benefits of vegan and vegetarian diets (1).
The proponents of such diets like to attribute these health benefits to the avoidance of animal foods.
However, there are many other factors at play.
A properly planned vegan diet consists primarily of whole foods. It is often called a Whole-Foods, Plant-Based (WFPB) diet.
This diet doesn’t just eliminate animal foods… it also eliminates a number of foods that science has shown to be harmful.
What else do they remove, besides animal foods? Let’s have a look…
- Refined sugar: Causes insulin resistance and fatty liver. Strong links to obesity, diabetes and heart disease (2, 3, 4, 5, 6).
- Refined grains: Lead to rapid spikes in blood sugar, insulin resistance and weight gain. Strong links to many chronic, Western diseases (7, 8, 9).
- Vegetable Oils: High in inflammatory Omega-6 fatty acids, increase inflammation and oxidative damage (10, 11, 12).
- Trans Fats: Extremely harmful, man-made fats found in processed foods and linked to many serious diseases, especially heart disease (13, 14).
Not to mention that these diets also eliminate processed foods… which are low in nutrients and high in harmful ingredients and artificial chemicals.
I personally find it plausible that the benefits of vegan diets are largely caused by avoiding processed foods and harmful ingredients like added sugar. It has absolutely nothing to do with avoiding unprocessed animal foods.
Bottom Line: The health benefits of vegan diets are likely caused by the elimination of harmful ingredients and processed foods. It has nothing to do with avoiding unprocessed animal foods.
2. Saturated Fat and Cholesterol Are Harmful Substances
The myth that animal fats cause heart disease still runs rampant among vegans.
In the past few years and decades, studies have shown this to be false… and experts all over the world are changing their minds.
Saturated fat and cholesterol actually lead to improvements in the blood cholesterol profile. They don’t make things worse, like previously believed (15).
A massive review study that looked at data from 21 other studies with a total of 347,747 participants concluded: There is absolutely no association between saturated fat consumption and heart disease (24).
Now… some vegan proponents may say that these studies shouldn’t be trusted because they’re funded by the meat, egg or dairy industries, but that is nonsense.
This has been studied intensely and it is NOT true that most of the studies are industry sponsored.
The truth is, saturated fat and cholesterol were wrongly demonized. The highest quality studies show them to be completely harmless for the majority of people.
Bottom Line: The myth that saturated fat and cholesterol lead to heart disease still runs rampant among vegans, but this myth has been thoroughly debunked in the past few years and decades.
3. A Vegan Diet is The Only Diet Proven to Reverse Heart Disease
It is often claimed that vegan diets are the only diet proven to reverse heart disease.
This idea is based on a number of studies by two doctors, Dean Ornish and Caldwell Esselstyn.
This goes beyond just biomarkers like cholesterol. They managed to partly reverse coronary heart disease. Impressive stuff, I’ll give them that.
However, I don’t think anything can be concluded about the vegan diet based on these studies. Let me explain why…
Ornish’s approach involves a lifestyle intervention. His patients also exercise, quit smoking and do meditation… along with other health promoting things. His diet was also not a vegan diet, but a low-fat vegetarian diet (28).
It is very clear that studies that use drugs or exercise (massive confounders) along with a diet can NOT be used to make claims about the diet.
In order to attribute the benefits of the intervention to the diet, then you need to isolate diet as the only variable that is different between groups.
Bottom Line: There are some studies showing a low-fat vegan/vegetarian diet to reverse coronary heart disease. However, these studies also used drugs or health promoting things like exercise and meditation.
4. The China Study
In almost every argument about vegan diets or animal foods, someone brings up The China Study.
This is a book that was written by biochemist and nutrition researcher T. Colin Campbell.
The book makes a case for animal foods (animal protein, in particular) being the main driver of killer diseases like heart disease and cancer.
The case is loosely supported with data from a massive epidemiological study called The China-Cornell-Oxford Project, along with a number of other observations and studies on rats.
Then he uses confusing terminology to make it seem like the rat studies using isolated proteins like casein have anything to do with diet and cancer in humans.
The book has been criticized by a number of people who have analyzed the findings:
- Dr. Chris Masterjohn: What Dr. Campbell Won’t Tell You About The China Study
- Denise Minger: The China Study – Fact or Fallacy
- Dr. Michael Eades: The China Study vs the China study
The findings of The China Study have also been contradicted by various other studies, some of which are of a much higher methodological quality.
This includes a recent study from Asia… a study with 112,310 men and 184,411 women, showing that red meat consumption was associated with reduced risk of heart disease in men and reduced risk of cancer in women (30).
The China Study is NOT about nutrition science. It belongs in the science fiction section of the library.
Bottom Line: The China Study has been thoroughly debunked by objective scientists and there are multiple high quality studies that contradict its findings, all of which were ignored by the author.
5. Animal Protein is Harmful
It is often claimed by vegans that animal protein causes harm.
A lot of this is based on studies in rats, using isolated proteins and refined diets.
The results of rodent studies using highly unnatural and refined diets aren’t necessarily applicable to humans.
In many cases, human studies on diet end up leading to the exact opposite results of the rodent studies. This appears to be the case with animal protein.
In fact, almost every human controlled trial on protein, both animal and plant protein, shows it to be beneficial for health.
The evidence is mounting that most people should be eating more animal protein, not less (42).
Bottom Line: Despite the myth that animal protein causes harm, studies show that it leads to health benefits. This includes weight loss, improved bone health, lower blood pressure and reduced symptoms of diabetes
6. Humans Are Not “Designed” to Eat Animals
Some vegans claim that humans are naturally herbivores and that our bodies are not adapted to eating animals.
Our bodies are well adapted to meat consumption and we are perfectly capable of making full use of the nutrients found in meat.
In fact, our digestive systems don’t resemble those of herbivores at all.
We have short colons, long small intestines and plenty of hydrochloric acid in the stomach to help break down animal protein.
Also, the lengths of different parts of our digestive systems are somewhere in between the lengths typical for carnivores and herbivores, indicating that we are naturally “designed” to be omnivores (45).
The fact that vegans can’t function without B12 supplements or B12 supplemental foods is also a pretty strong argument for these diets not being “natural.”
Also, hunter-gatherers ate lots of meat. Our genes were shaped in an environment that included plenty of animal products (47).
The truth is… humans function best eating both animals and plants. Period.
Bottom Line: Humans are naturally omnivores and function best eating a combination of animals and plants. This is reflected in the anatomy of our digestive system.
7. Meat Causes Heart Disease, Diabetes and Cancer
Most chronic, Western diseases are relatively new.
The heart disease epidemic started around 1930, while type 2 diabetes started increasing rapidly in the late 20th century.
Cancer has also been on the rise for many decades.
Vegans like to blame meat and animal foods for these health problems.
However… meat is an old food and these health problems are relatively new.
Blaming new health problems on old foods makes absolutely no sense.
Let’s take a look at the health problems that meat is being blamed for and the highest quality evidence that examines these claims.
The cancer link is probably related to the way meat is cooked. Several studies suggest that it forms carcinogens when overheated, so it is important to use gentler cooking methods and avoid burning your meat (52).
Keep in mind that all of these studies found a significantly increased risk for people who consumed processed meat. Therefore, differentiating between the different types of meat is important.
It is well known that processed foods in general are harmful… this is not exclusive to meat.
Bottom Line: Studies that differentiate between processed and unprocessed meat show that unprocessed red meat is not associated with heart disease or diabetes, and only weakly linked to cancer in men, but not women.
8. Vegetarians and Vegans Live Longer and Have a Lower Risk of Killer Diseases
However, these studies are plagued by a phenomenon called the healthy user bias.
What this implies, is that vegetarians are generally more health conscious than meat eaters.
Therefore, it is impossible to claim that they are healthier because they avoid meat. Maybe they’re healthier because of the other health promoting things that they do.
Who knows… maybe they’re healthier despite (not because of) avoiding meat.
In one study, researchers found a clever way to control for the healthy user bias.
They recruited participants that were customers of a health food store, looking at the difference between health conscious vegetarians and health conscious meat eaters.
Guess what… they found no difference in mortality or the risk of heart disease or stroke (56).
What this implies is that the reason vegetarians live longer and have a lower risk of some diseases, is because they tend to be health conscious people. It has absolutely nothing to do with avoiding animal foods.
Bottom Line: The observational studies showing that vegetarians and vegans are healthier, are plagued with the healthy user bias. Studies that control for health consciousness show no effect.
9. Low-Carb Diets Will Kill You
Vegans really hate low-carb diets.
This is understandable, because low-carb diets are almost the complete opposite of vegan and vegetarian diets.
This study compared Atkins (a low-carb diet) and Ornish (a low-fat vegetarian diet) in a group of overweight/obese premenopausal women.
After a period of 1 year:
- The Atkins group lost more weight than the Ornish group (10.4 vs 5.6 pounds) – the difference was not statistically significant at 12 months.
- The Atkins group had greater decreases in blood pressure.
- The Atkins group had greater increases in HDL cholesterol.
- The Atkins group had a 29.3 mg/dL reduction in triglycerides, compared to 14.9 mg/dL in the Ornish group.
The people in the Ornish group had trouble sticking to the diet and were twice as likely to drop out of the study, indicating that the Atkins diet was easier to follow.
This is the best study available that compares low-carb and low-fat vegetarian diets. The results are clear.
Until another controlled trial leads to a different result, there is absolutely no scientific basis for vegan proponents to claim that low-carb diets are inferior to vegan diets from a health perspective.
Additionally… many other studies have been conducted on low-carb diets. Since the year 2002, over 20 randomized controlled trials have demonstrated that low-carb diets are superior to low-fat diets.
Bottom Line: It is not true that low-carb diets are harmful. The only study that properly compared low-carb to a low-fat vegetarian diet showed that the low-carb diet was much healthier.
10. There is a Lot of Evidence Behind Vegan Diets
Vegan proponents often make it seem like there are many studies demonstrating the health benefits of vegan diets.
However… there is only one controlled trial (real science) where they isolate diet as the sole variable and compare against another dietary intervention.
This study is the only study I am aware of (and I’ve looked hard and asked many vegans if they know of more studies) that actually tests the vegan diet directly.
Therefore, this study is the best one to accurately reflect the true health effects of the diet.
The study was conducted, among others, by doctors Neal Barnard and David Jenkins.
It compared a low-fat vegan diet to a typical diabetes diet based on the guidelines of the American Diabetes Association. The participants were individuals with type 2 diabetes.
These were the results after a 74 week study period (58):
- Vegan group lost 9.7 lbs, diabetes diet group lost 6.6 lbs. The difference was not statistically significant.
- Only after adjustments (statistical manipulation) were there small advantages for the vegan diet for HbA1c (-0.40% vs +0.01%), Total cholesterol (-20.4 vs -6.8 mg/dL) and LDL (-13.5 vs -3.4 mg/dL).
- No difference in weight, BMI, waist circumference, HDL cholesterol, triglycerides, blood pressure, fasting blood sugars or CRP levels.
Really… this is it. These are the “miraculous” benefits of the vegan diet in the most comprehensive study on a low-fat vegan diet to date.
Not quite as impressive as the vegan docs make it out to be in their books and documentaries…
Keep in mind that the lead researchers are both vegans themselves, so they should be able to set up a study that maximizes the benefits of such a diet.
There is absolutely nothing groundbreaking about these results. Studies on other diets, like Mediterranean, paleo or low-carb, have lead to similar and often much better results.
Given all the hype about vegan diets, I have to say that the results are underwhelming… to say the least.
Bottom Line: In the best controlled trial on vegan diets to date, there is very little difference compared to a typical diabetes diet that includes animal foods.
11. Vegan Diets Can Easily Supply All Necessary Nutrients
Some vegan proponents claim that it is possible to obtain all necessary nutrients without animal foods.
However… this is easier said than done and it seems that many vegans are having problems.
Nutrient deficiencies are much more common among vegans:
- Vitamin B12: 83% of vegans are deficient in B12, compared to 5% of omnivores. B12 deficiency can have serious consequences (59).
- Iron: In one study, vegetarians had only a third of the ferritin (a marker for iron levels) of omnivores (60).
- Vitamin D: Levels of Vitamin D are 74% lower in vegans, compared to omnivores (61).
- Omega-3 Fatty Acids: Vegans have 53% lower levels of EPA and almost 59% lower levels of DHA, compared to meat eaters (62).
A diet that makes the majority of people who follow it deficient in critical nutrients…
I don’t know about you, but that seems like a pretty bad idea to me.
2015 Update: I have changed my mind about vegan diets since writing this article. I think these diets can be healthy for many people, as long as they are properly planned and based on whole, unprocessed foods.