Book excerpt: The explosion of knowledge about satiety and hunger has given new meaning to our understanding of the genetics of obesity. New interest in gene expression as related to nutrition and advances in the field of macronutrients has made the latest nutrition research intriguing. Advanced Nutrition: Macronutrients adopts an integrated approach to the understanding of macronutrient nutrition. It provides scientific foundations of the current findings on energy balance, protein need, gene expression, and carbohydrate and lipid use, and maintains emphasis on the biochemical and physiological basis for nutrient need.