Some of my elderly (50+) neighbors are skin and bone as they always were.
They don't get much out of the village, no donuts, no pizza, no fatty icecream, no deep fried fat dripping chicken, no hypersweet drinks etc.etc.etc.
They simply don't have the money for all that.
Easy explains why they are still slim like the even poorer Laos fellows (who have basically the same lifestyle).
They have no need for exercise. One neighbor 70+ is on the fields daily and works in the sweltering sun. No treadmills after work.
Look at the world center of fattys and find the answers. Easy.