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.