Let’s explore our human machinery. And talk about Brazilian butt lifts. Professor of Evolutionary Anthropology and metabolism researcher Dr. Herman Pontzer gives us the data on mitochondrial backstories, muscle mass and hormones, our expanding brains, the flaws of the Body Mass Index, humans’ relationships with nutrition, why crash dieting can change your metabolism, perspectives on sticky medical terms, isotope magic, how much exercise hunter gatherers get, carnivore diets, scales, and what to do if you're grappling with sadness. Content warning: we discuss diet culture, calories, how the word “obesity” is used, medical conditions that may relate to body composition, and highlight listeners’ lived experiences.