“As the athletes’ ran more and more over weeks or months, their metabolic engines cut back elsewhere to make room for the extra exercise costs, Pontzer says.”
Hadza hunter-gatherers walk all day and burn about the same calories as office workers in Illinois. The body has a budget, and it cuts spending elsewhere when you run more. The fitness industry sells exercise as a weight loss plan. The data says it’s a health plan, and your fork does the weight loss.