I’ll be honest, this is a pretty poor article. It focuses solely on macronutrients but doesn’t even touch on satiety. Sure, some random tribe may eat 50% more carbs than we do, but the difference is our calories come from low satiety carbs such as high fructose corn syrup, and their carbs come from sweet potatoes, one of the more satisfying foods to eat. So it can hardly be called a “mystery” why a more physically active, lower calorie lifestyle produces a group of people who are healthier. It’s throwing a ton of stats at you that sound plausible but break down under scrutiny. Not to mention this is just the “mysteries”, and no actual hypotheses are drawn.
