You've probably never given thought to what your ancestors stuffed down their gullets. Now might be the time. In a new study in Molecular Biology and Evolution, Cornell University researchers explain that people who come from a line of mostly plant eaters likely carry a gene mutation used to help compensate for a lack of essential fatty acids from meat or fish.

The problem is that those who have the mutation—about 70 percent of South Asians, 53 percent  of Africans, 29 percent of East Asians, 17 percent of Europeans, and 18 percent of Americans, per Australia Network News—can actually hurt their bodies with a fatty acid overload, particularly if their diet is heavy in things like meat and sunflower oil, reports the Australian.

The result is an increased risk of heart disease, colon cancer, and chronically high inflammation. Researchers identified the mutation in the FADS2 gene when comparing 234 people from Pune, India, where populations have historically eaten a plant-based diet, with 311 meat eaters from Kansas.

Some 68 percent of the Indians had two copies of a sequence of DNA used to regulate genes FADS1 and FADS2—which make long-chain polyunsaturated fats like omega-3 and omega-6, used for brain development and to curb inflammation—compared to just 18 percent of the Americans, reports Metro.

While the gene came in useful generations ago, "changes in the dietary omega-6 to omega-3 balance may contribute to the increase in chronic disease seen in some developing countries," researchers say in a release.

People with South Asian and southern African ancestry are particularly prone to high inflammation. (This population produces very little fatty acid.)

This article originally appeared on Newser: Vegetarian Ancestors Affect Your Cancer Risk

More From Newser