Effect of weight loss and ketosis on postprandial cholecystokinin and free fatty acid concentrations.

BACKGROUND

Weight regain after weight loss may not be due primarily to voluntary return to social habits but may be explained by changes in peripheral hormonal signals activating hunger and encouraging feeding behavior.

OBJECTIVE

The objective of this study was to investigate physiologic adaptations to weight loss that may encourage weight regain.

DESIGN

The study had a within-subject repeated-measure design [12 healthy, obese men, 33-64 y, body mass index (in kg/m(2)) 30-46] and was a clinical intervention investigation of circulating metabolites and hunger-satiety responses before and after weight loss. Measures included anthropometry (bioelectrical impedance, body weight, and waist circumference), concentrations of circulating hormones and metabolites [ketone bodies, free fatty acids (FFAs), insulin, leptin, glucose, and cholecystokinin (CCK)], and measures of hunger and satiety at baseline, 8 wk after weight loss with a very-low-energy diet, and 1 wk after weight maintenance.

RESULTS

Weight loss led to a reduction in postprandial CCK secretion (P = 0.016). However, when subjects were ketotic (elevated circulating beta-hydroxybutyrate concentrations), CCK secretion was sustained at concentrations before weight loss. After weight loss, there were reduced postprandial FFA concentrations (P = 0.0005). The presence of ketosis sustained FFA to concentrations before weight loss (P = 0.60).

CONCLUSION

Rapid weight loss of approximately 10% of initial body weight results in a reduction in postprandial CCK and FFA concentrations.