Studies suggest that indigenous groups get into trouble when they abandon their traditional diets

 Studies suggest that indigenous groups get into trouble when they abandon their traditional diets 

 active lifestyles for Western living. Diabetes was virtually unknown, for instance, among the Maya of Central America until the 1950s. As they’ve switched to a Western diet high in sugars, the rate of diabetes has skyrocketed. Siberian nomads such as the Evenk reindeer herders and the Yakut ate diets heavy in meat, yet they had almost no heart disease until after the fall of the Soviet Union, when many settled in towns and began eating market foods. Today about half the Yakut living in villages are overweight, and almost a third have hypertension, says Leonard. And Tsimane people who eat market foods are more prone to diabetes than those who still rely on hunting and gathering.

For those of us whose ancestors were adapted to plant-based diets—and who have desk jobs—it might be best not to eat as much meat as the Yakut. Recent studies confirm older findings that although humans have eaten red meat for two million years, heavy consumption increases atherosclerosis and cancer in most populations—and the culprit isn’t just saturated fat or cholesterol.

 Our gut bacteria digest a nutrient in meat called L-carnitine. In one mouse study, digestion of L-carnitine boosted artery-clogging plaque. Research also has shown that the human immune system attacks a sugar in red meat that’s called Neu5Gc, causing inflammation that’s low level in the young but that eventually could cause cancer. “Red meat is great, if you want to live to 45,” says Ajit Varki of the University of California, San Diego, lead author of the Neu5Gc study.