Postprandial ghrelin responses are associated with the intermeal interval in   time-blinded normal weight men, but not in obese men.
OBJECTIVE
To investigate the relation between ghrelin responses and meal initiation and the effects of BMI and energy status on this.


METHODS
The experiment had a randomised, cross-over design.


METHODS
Nine 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.


METHODS
Subjects 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.


RESULTS
Postprandial 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.


CONCLUSIONS
Meal-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.
Blom
Wendy A M
WA
TNO Quality of Life, Zeist 3700 AJ, The Netherlands
de Graaf
Cees
C
Lluch
Anne
A
Stafleu
Annette
A
Schaafsma
Gertjan
G
Hendriks
Henk F J
HF
D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D031204:Caloric Restriction; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology*; D018592:Cross-Over Studies; D002149:Energy Intake / Q000502:physiology*; D005215:Fasting / Q000097:blood; D005247:Feeding Behavior / Q000502:physiology; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D006815:Hunger / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D019518:Postprandial Period; D012016:Reference Values; D016037:Single-Blind Method; D018709:Statistics, Nonparametric; D013997:Time Factors; D055815:Young Adult
D001786:Blood Glucose; D054439:Ghrelin