The protein content of the diet is important for its effect on eating patterns. High-protein diets promote satiety and reduce calorie intake, whereas low-protein diets give less consistent results. Protein sensing might take place in the oral cavity or in the upper gastrointestinal tract, where specific receptors have been found. Protein signalling to the brain may act through the vagus nerve and involve gastric hormones, such as cholecystokinin and peptide YY. Other pathways are post-absorptive signalling and the direct influence of brain levels of amino acids. High-protein diet enhances the activity of brain satiety centres, mainly the nucleus of the solitary tract and arcuate nucleus, although the activity of brain reward centres might also be modified. This is a fruitful area for research.
Davidenko O et al 2013 Control of protein and energy intake – brain mechanisms European Journal of Clinical Nutrition (2013) 67, 455–461;