I've seen claims like this a lot:
"There are races of people who are all slim, who are stronger and faster than us. They all have straight teeth and perfect eyesight. Arthritis, diabetes, hypertension, heart disease, stroke, depression, schizophrenia and cancer are absolute rarities for them. These people are the last 84 tribes of hunter-gatherers in the world."
Is that actually true though? It seems like the sort of thing that should be easy to verify or disprove. Whether it's actually caused by diet would be harder to prove, but if these people really are free of all those health problems, that would be quite remarkable and should be studied more carefully.
There is a really good book out right now called "Healthy at 100" by John Robbins that speaks to this very subject. It looks at several cultures that tend to have a larger % of HEALTHY centenarians, such as the Okinawans and Hunzans. It looks at what they eat, how they live, etc. It is good because he acknowledges the self-reporting errors in such studies ("Yeah, dude, I'm 110 years old!") and the impact of physical activity and social bonds on longevity, etc.
John Robbins is biased (toward vegetarianism/veganism), but his bias is based on sound principles (science, self-experience, environmental impact, ethics, etc.) The book is not preachy or anything, though. His other books are also really good. Especially if you're interested in the food industry, animal cruelty, nutrition and disease, etc.
He's a very interesting guy. He walked away from the Baskin-Robbins fortune to live a simpler and healthier life after his dad and uncle (Robbins and Baskin, respectively) both died of heart disease from eating too much of their own product. His one room, self-built cabin with second-hand furniture was featured on "Lifestyles of the Rich and Famous" and it became one of their most requested shows, to everyone's surprise. He's a pretty inspiring guy.
Well, to some degree it may be true because if you are afflicted with something nasty, you die, quickly. That, and not living a sedentary lifestyle are two things that would leave the survivors pretty healthy.
Is that actually true though? It seems like the sort of thing that should be easy to verify or disprove. Whether it's actually caused by diet would be harder to prove, but if these people really are free of all those health problems, that would be quite remarkable and should be studied more carefully.