Anyone who wants the full benefit and results of CrossFit must understand--and then act on the information--that nutrition is the foundation for all the other work you do in the name of athletic development and elite health. The key, of course, is hormones, which regulate how the body stores and releases energy and repairs itself. And, as far as hormones are concerned, food is a drug--a very powerful drug. It is the regulator for your body's internal teeter-totter, where the interdependent levels of "good" and "bad" hormones pivot on the food you take in. The simple CrossFit nutrition prescription--"Eat meat and vegetables, nuts and seeds, some fruit, little starch, and no sugar"--will deliver you from metabolic derangement (i.e., hyperinsulinemia, Syndrome X, and their relatives) and keep you generally well. For maximal fitness and output, however, you need to be more precise than that. In this lecture excerpt, Nicole Carroll makes a compelling case for why.