This excerpt from Dr. Valter Longo's "The Longevity Diet" explains his research on aging and longevity, focusing on the role of nutrition. Dr. Longo argues that aging is a programmed process, not a natural consequence of cell damage, and emphasizes the importance of rejuvenation rather than just protection against aging. He proposes a "Longevity Diet" that combines a mostly plant-based diet with periodic fasting-mimicking diets (FMD) to activate the body's natural repair and regeneration mechanisms. He explores the applications of this diet in preventing and treating various diseases, including cancer, diabetes, cardiovascular disease, neurodegenerative diseases, and autoimmune diseases. The book also explores the importance of exercise and the role of coffee and coconut oil in promoting longevity.