What if we told you that some of the healthiest people on the planet subsist mainly on a diet of monkey meat, piranha flesh, and wild pig chops—that, and a smattering of foraged fruits and nuts, plus some corn and rice, not a head of broccoli or a kale salad in sight?

That's the reality for the Tsimane, a tribe of about 16,000 hunter-gatherers who live in the Amazon rain forest in Bolivia. The Tsimane were recently studied by a team of researchers from the University of New Mexico, who discovered—with some amazement— that about 9 in 10 of the Tsimane had zero risk for developing heart disease.

“Our study shows that the Tsimane indigenous South Americans have the lowest prevalence of coronary atherosclerosis of any population yet studied,” said senior author, Hillard Kaplan, Ph.D. “Their lifestyle suggests that a diet low in saturated fats and high in non-processed, fiber-rich carbohydrates, along with wild game and fish, not smoking, and being active throughout the day could help prevent hardening in the arteries of the heart.”

The researchers found that while Westerners are inactive about 50% of the day, the Tsimane were only idle for 10% of their waking hours. The men averaged about 17,000 steps a day, with the women pulling in 16,000. Their diet is about three-quarters carbs—rice, plantain, corn, nuts, and fruit—with the rest evenly split between protein (which comes from wild game) and fat, representing about 38 grams, 11 of which come from saturated fat. And get this: Only 3% were tagged with moderate or high risk of heart disease, compared to about 50% of the typical American population.

That lifestyle isn't all upside, of course: The researchers did find that even though the risk of developing coronary atherosclerosis is low, 67% have intestinal worms, 1% likely had tuberculosis, and about half of the population had high rates of inflammation due to constant infections. But the study illustrates that adopting the good parts of their life in the rain forest—being physically active, not smoking, eating an entire diet low in saturated fats—can be a simple way to fight back against the high rates of heart disease seen in the industrialized world.