Protein-dependent regulation of feeding and metabolism

• Dietary protein is an essential nutrient that is required for health.
• Variations in protein quality or quantity robustly alter food intake.
• The intake of protein appears to be regulated independently of other nutrients.
• Protein-specific mechanisms offer novel opportunities for the treatment of obesity.

Free-feeding animals often face complex nutritional choices that require the balancing of competing nutrients, but the mechanisms driving macronutrient-specific food intake are poorly defined. A large number of behavioral studies indicate that both the quantity and quality of dietary protein can markedly influence food intake and metabolism, and that dietary protein intake may be prioritized over energy intake. This review focuses on recent progress in defining the mechanisms underlying protein-specific feeding. Considering the evidence that protein powerfully regulates both food intake and metabolism, uncovering these protein-specific mechanisms may reveal new molecular targets for the treatment of obesity and diabetes while also offering a more complete understanding of how dietary factors shape both food intake and food choice.