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.
Level 2 - randomized trial
Individual randomized crossover trial
PubMed 22556143 · doi:10.1152/ajpgi.00478.2011
What was done
Thirty-two men (16 lean, 16 obese) were evaluated on four separate test days in a crossover design. Following a standardized breakfast, subjects consumed one of four isocaloric lunch meals varying in macronutrient composition and protein load: high-fat (HF), high-protein (HP), high-carbohydrate/low-protein (HC/LP), or adequate-protein (AP). Appetite ratings (hunger, fullness) and plasma gastrointestinal hormones (cholecystokinin, peptide YY, and ghrelin) were measured over 180 minutes, followed by quantification of energy intake at a buffet meal.
What was found
The abstract reports directional significance without numerical values. In lean men, hunger was lower and fullness higher after HF, HP, and AP meals compared with HC/LP meals, and subsequent buffet energy intake was lower following HF and HP compared with HC meals (P < 0.05). In obese men, hunger was lower after HP compared with HF, HC/LP, and AP meals, and energy intake was lower after HP and AP compared with HF and HC meals (P < 0.05). Hormone responses showed no major differences between groups, but CCK and ghrelin responses were sustained following HP and AP meals in both cohorts.
Why it matters
Modest, sustainable increases in protein intake acutely curb hunger and reduce subsequent meal energy intake in both lean and obese individuals, whereas obese men show attenuated satiating responses to dietary fat.
Limits
The sample was limited to 32 adult men, precluding generalization to women. The design evaluated only acute single-meal responses over 180 minutes, with no assessment of cumulative 24-hour energy intake or long-term body weight changes. Specific numerical values for appetite scores, hormone concentrations, and caloric intake were omitted from the abstract.
Cited by
- supports Protein is the most satiating of the macronutrients, more so than carbohydrates and fat.