Our guest is Herman Pontzer, an Associate Professor of Evolutionary Anthropology at Duke University and Associate Research Professor of Global Health at the Duke Global Health Institute. An well-known researcher in human energetics and evolution, he joins us to discuss his new book, "Burn: New Research Blows the Lid Off How We Really Burn Calories, Lose Weight, and Stay Healthy." The book draws on Pontzer's groundbreaking studies with hunter-gatherer tribes in order to show how exercise actually **doesn't** increase our metabolism. Instead, human beings generally burn calories within a very narrow range -- nearly 3,000 calories per day, no matter our activity level. The book thus offers, per a starred review in Kirkus, "an absorbing, instructive lesson for anyone concerned about their health."