Peptide Research News - Effects of fat, protein and carbohydrate, and protein load, on appetite, plasma cholecystokinin, peptide YY and ghrelin, and energy intake in lean and obese men.

Effects of fat, protein and carbohydrate, and protein load, on appetite, plasma cholecystokinin, peptide YY and ghrelin, and energy intake in lean and obese men.

Am J Physiol Gastrointest Liver Physiol. 2012 May 3;

Authors: Brennan IM, Luscombe-Marsh ND, Seimon RV, Otto B, Horowitz M, Wishart JM, Feinle-Bisset C

Abstract
While protein is regarded as the most satiating macronutrient, many studies have employed test meals that had very high, and unsustainable, protein contents. Furthermore, the comparative responses between lean and obese subjects, and the relationships between energy intake suppression and gut hormone release remain unclear. We evaluated the acute effects of meals with modest variations in (i) fat, protein and carbohydrate content, and (ii) protein load, on gastrointestinal hormones, appetite and subsequent energy intake in lean and obese subjects. 16 lean and 16 obese males were studied on 4 occasions. Following a standardized breakfast, they received for lunch, i) high-fat ('HF'), ii) high-protein ('HP'), iii) high-carbohydrate/low-protein ('HC'/'LP') or iv) adequate-protein ('AP'), isocaloric test-meals. Hunger, fullness and gut hormones were measured throughout, and at t=180 min, energy intake at a buffet-meal was quantified. In lean subjects, hunger was less, and fullness greater, following HF, HP and AP, compared with HC/LP, meals, and energy intake was less following HF and HP, compared with HC, meals (P<0.05). In the obese, hunger was less following HP, compared with HF, HC/LP and AP, meals, and energy intake was less following HP and AP, compared with HF and HC meals (P<0.05). There were no major differences in hormone responses to the meals between subject groups, but the CCK and ghrelin responses to HP and AP were sustained in both groups. In conclusion, HP meals suppress energy intake in lean and obese subjects, an effect potentially mediated by CCK and ghrelin, while obese individuals appear to be less sensitive to the satiating effects of fat.

PMID: 22556143 [PubMed - as supplied by publisher]