There's A Reason Vegetarians Can't Stand Meat, According To Science

People become vegetarians for a lot of reasons. Some are born into religions or cultures that favor plant-based diets while others choose, later on in life, to avoid meat for ethical, economic, or health reasons. After all, there is some science to indicate that eating a properly planned vegan or vegetarian diet — one that meets your nutritional requirements — can ward off heart disease and other chronic illnesses, per Harvard Health

But what if there is another reason why vegetarians prefer meat? According to a 2023 study led by Dr. Nabeel Yaseen, an emeritus professor of pathology at Northwestern University's Feinberg School of Medicine, there could be a genetic link to why some people prefer a plant-based diet over meat. The study analyzed data from the UK Biobank of 5,324 strict vegetarians (no fish, poultry, or red meat) and 329,455 others who ate meat. 

"At this time we can say is that genetics plays a significant role in vegetarianism and that some people may be genetically better suited for a vegetarian diet than others," Dr. Yaseen shared with CNN Health. So, how can genes dictate who favors what?

It might have to do with variations in lipid metabolism

Researchers of the study found three strongly identified "vegetarian genes" and 31 other potential "vegetarian genes" in their subjects. The vegetarians in the study were more likely than meat eaters to have different variations of these genes, and the meat eaters did not possess four variations of the so-called "vegetarian genes" – TMEM241, RIOK3, NPC1, and RMC1 (via the Daily Mail).

The theory is that these genes are involved in how the human body breaks down fat, i.e., lipid metabolism, per Northwestern Now. The same enzymes that break down fat in meat won't work on a plant-based diet. They both require different enzymes to get the job done. So the idea is that how well your body breaks down fat from either plants or meats might be driving you to prefer one diet over the other, per the study.

"One area in which plant products differ from meat is complex lipids. My speculation is there may be lipid component(s) present in meat that some people need. And maybe people whose genetics favor vegetarianism are able to synthesize these components endogenously," explained Dr. Nabeel Yaseen (via Northwestern Now). The study also found that some subjects (48 to 64%) who identified as vegetarians admitted to eating meat sometimes. Dr. Yaseen, again, associates this finding with the theory that some people are more hard-wired to prefer meat to a plant-based diet and vice versa. 

What does this mean for vegetarianism?

It's important to keep in mind that this is just one study done on one type of group – white Caucasians. The idea that we might be genetically more inclined to prefer one diet (meat or vegetarian) or food type over another isn't necessarily a well-researched one. 

When commenting on the study to CNN Health, Dr. José Ordovás, the director of nutrition and genomics and professor of nutrition and genetics at Tufts University in Massachusetts, shared that while this type of research does create conversation about dietary choice being determined by more than just culture, ethics, environment, or health, "this study shines a light on a relatively under-explored area of research: the genetics behind dietary preferences." More science-based research is definitely needed, added Dr. Nabeel Yaseen, per Northwestern Now. 

But right now, the information available at hand could get you thinking about why some people might exercise better self-control when it comes to sticking to a plant-based diet, abstaining from alcohol, or even laying off sweet treats. Could it be that their genes are helping them in some way?