Postprandial ghrelin responses are associated with the intermeal interval in time-blinded normal weight men, but not in obese men

ObjectiveTo investigate the relation between ghrelin responses and meal initiation and the effects of BMI and energy status on this.DesignThe experiment had a randomised, cross-over design.Setting and subjectsNine normal-weight (age: 33.2 ± 4.8 y, BMI: 23.2 ± 0.5 kg/m2) and eleven obese (age: 40.8 ±4.7 y, BMI: 33.2 ± 0.8 kg/m2) healthy men were recruited from a pool of volunteers and by advertisements.InterventionsSubjects followed a three-day energy restrictive and a three-day energy balanced diet separated by one month. Each diet was followed by a time-blinded (overnight) stay at the research facility. Subjects received a breakfast (preload) and were instructed to ask for lunch when they felt hungry. Ghrelin, insulin, glucose, free fatty acids, appetite, IMI and energy intake during lunch were assessed.ResultsPostprandial decreases in ghrelin (r = − 0.54; p < 0.05) and the AUC of the ghrelin response (r = − 0.57, p = 0.01) were associated with the intermeal interval, independent of diet, but in normal weight subjects only. Lunch request was preceded by an increase in ghrelin, reaching at least 93% of fasting values. These preprandial increases in ghrelin were correlated with IMI, after energy restriction only. Ghrelin concentrations but not changes in ghrelin were correlated with appetite.ConclusionMeal-related changes in ghrelin are correlated with the IMI in normal weight subjects only, independent of diet. Ghrelin concentrations may need to reach a certain threshold level before the next meal is initiated.SponsorshipSupported by Dutch Ministry of Education, Culture and Science, Dutch Ministry of Health, Welfare and Sport and Danone Research.