Objective and subjective appetite measures: high versus low eating frequency in a randomized crossover clinical trial

The objective of this study was to examine objective (ghrelin and peptide YY [PYY]) and subjective appetite measures following 21-day high and low eating frequency (EF) interventions among healthy adults.

In the randomized crossover trial (Frequency of Eating and Satiety Hormones [FRESH] study), participants completed two eucaloric 21-day study periods of low (3 meals/day) and high (6 meals/day) EF with a 14-day washout period. Self-selected foods and total energy consumed were identical in both arms. On day 21 of each period, participants completed a 7-h clinic visit with meals provided according to assigned EF. Postprandial plasma ghrelin and PYY concentrations were assessed through serial blood draws (hourly), and self-reported appetite ratings were collected every 30 min.

Fifty participants were recruited and completed the trial (mean age, 32 years, 78% women, and 60% non-Hispanic White). High EF resulted in smaller changes in postprandial ghrelin and PYY concentrations compared to low EF, with significant area under the curve differences between groups (p value for ghrelin = 0.03; p value for PYY < 0.001). Similar patterns were found in self-reported hunger, desire to eat, and fullness. Differences in postprandial PYY were greater among participants with overweight/obesity or high body fat percentage.

High EF led to smaller changes in objective and subjective appetite measures, suggesting that small frequent meals may lead to blunted satiety and less optimal appetite regulation.