People usually say they go vegan for one of two reasons: ethics, or health.
I think most people imagine vegans to be healthier instinctively, but it’s rarely backed up by solid evidence.
So is it true? Is it healthier to be vegan than a meat eater? And if so, by how much?
Almost every article I’ve read on this topic has been biased one way or the other.
They cherry pick weak studies or misinterpret the results. The authors are often scientifically illiterate and don’t understand basic statistics concepts.
This is my attempt to answer the question based on valid evidence. I’m going to go over several studies for you, and clearly outline which conclusions we can actually draw from them.
Ultimately, we’ll answer the original question in the title the best we can.
What Does “Healthier” Mean?
Before we look at studies, we have to be on the same page.
Ask different people what “healthy” means, and you’ll get different answers:
- Full of energy
- Good immune system
And so on…
But when it comes to studies, we’re mainly looking at 3 things:
- Body mass index (BMI) – Correlates strongly with obesity, and is a significant risk factor for a number of diseases (diabetes, cancer, heart disease), as well as mortality overall.
- Heart disease (CVD)
We’ll be mainly looking at studies that focus on those.
Vegans vs Meat Eaters: BMI and Weight Gain
Let’s start with BMI.
Some of the best data available is courtesy of EPIC-Oxford, a prospective cohort of 65,000 people in the UK.
It’s been running since 1993, and several studies have analyzed the ongoing data collected over time.
One such study, published in the International Journal of Obesity, found a few significant age-adjusted correlations between diet and BMI:
- BMI was highest in meat eaters
- BMI was in the middle for both fish-eaters and vegetarians.
- BMI was lowest in vegans
The authors controlled for lifestyle factors such as smoking, physical activity, and education level.
The most influential factors that contributed to a higher BMI were high protein and low fiber in the diet.
One other study in the UK also looked at weight gain over a 5 year period.
Here was their main conclusion:
Small differences in weight gain were observed between meat-eaters, fish-eaters, vegetarians and vegans. Lowest weight gain was seen among those who, during follow-up, had changed to a diet containing fewer animal food.
It’s worded a bit confusingly. In plain English, it means that people who were already on a specific diet gained the same amount of weight, regardless of eating meat or not.
But those participants who started the study as meat eaters, and transitioned towards veganism tended to gain the least weight.
This suggests that going vegan may help you lose weight in the beginning. But, over time, most people tend to gain weight, regardless of diet.
Vegans vs Meat Eaters: Cancer
I’m not sure why so many studies around this topic are based in the UK, but I’m thankful for them.
This next study took place over 20 years and collected data on 35,000 women in the UK, funded by the World Cancer Research Fund.
Specifically, it looked at breast cancer. The conclusion is pretty clear:
The study has demonstrated a positive association between meat intake and risk of breast cancer. Women, both pre- and postmenopausal, who consumed the most meat had the highest risk of breast cancer.
The one other significant note was that fish eaters that didn’t eat meat get some benefit when it comes to breast cancer.
Fish Eaters and Vegetarians Have Lower Overall Cancer Rates
This next study looked at just under 5,000 cases of cancer, with an average follow-up period of 14.9 years (a decent length).
For the most part, there wasn’t a significant difference in cancer rates between vegans and meat eaters.
However, for specific types of cancers, there were significant differences in relative risk (RR):
- Lymphatic/hematopoietic tissue
- Multiple myeloma
Putting it all together, both fish eaters and vegetarians had relative risks of ~0.88 compared to meat eaters for all types of cancer combined.
So while the vegans and fish eaters were less likely to get cancer, it’s not by a huge amount, especially when you consider that the chance to get cancer is relatively low in the first place.
Certain Types of Meat May Increase Cancer Mortality
Note that all these studies so far group all vegans together, and all meat-eaters together.
So someone who eats a chicken breast a week is in the same group as the person who eats red meat 3 times a day.
Some studies have started to look at the difference between eating specific types and quantities of meat when it comes to health.
This study found that
Red meat consumption is associated with an increased risk of total, CVD, and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.
Vegans vs Meat Eaters: Heart Disease
The final big aspect of health that we’re looking at is heart disease.
This is already impacted by BMI, but I was able to find a good study, once again from the UK, that looked at ischaemic heart disease.
They found that vegetarians have lower rates of ischaemic heart disease.
However, they were not able to isolate the impact of lifestyle factors. For example, the researchers found that vegetarians also smoke less, which at least partially explains the rates of heart disease.
Therefore, while a vegan diet may reduce the risk of heart disease (it certainly doesn’t seem like it increases it), we can’t make a conclusion until a more comprehensive study is done.
Studies Against Veganism Being Healthier
So far, every major study has said that being vegan is at least as healthy as eating meat, and in most cases it’s significantly healthier.
But if you go on certain websites, and play around with your Google searches, you will see some “data-backed” blog posts that claim that vegans are less healthy.
So what’s happening here?
To try and be fair, I dug around for a while. Every article that claimed this contrary position pointed to this Austrian study.
The study concludes:
Moreover, our results showed that a vegetarian diet is associated with poorer health (higher incidences of cancer, allergies, and mental health disorders), a higher need for health care, and poorer quality of life
The NHS has published a great writeup of why the “conclusion” of this study is being blown out of proportion.
Despite the media headlines, the results from this Austrian cross sectional survey provide no proof that vegetarians are in poorer health than meat eaters.
I encourage you to read the full NHS write-up about the limitations of the study.
But in short, the sample size of vegetarians was rather small, and crude categorizations of diseases and health variables were measured. It also only looked at Austrian vegetarians, and they may have different lifestyle habits that vegetarians elsewhere.
That doesn’t mean the study is worthless, but it’s a singular study with heavy limitations.
I think it’s very possible that vegans struggle more with mental health for quite a few reasons. However, we need to see more research on specific topics like that in order to make a valid conclusion.
Solid arguments about whether or not something is healthier than another should not be based on single, limited studies.
Which is Healthier: Vegan Diets or Meat Eaters?
What we can say after all this is that vegans are generally healthier than meat eaters.
However, these studies grouped a lot of people together by broad diet types in order to analyze data. It certainly doesn’t mean that all vegans are healthier than meat eaters.
To continue on that point, a review of vegetarian and low-meat diets showed that both vegetarian diets and plant-based diets that contain small amounts of meat also bring health improvements over the typical meat-based diet.
As we move forward, more studies will hopefully look at these granular differences to determine what the optimal diet is for those looking to maximize their health.
For now, all we can conclude is that in just about all cases, eating more plants and less meat is a good thing.
If you’re currently an omnivore, then you’ll probably benefit from reducing meat consumption a bit, particularly red meat.