Changes in 24-h area-under-the-curve ghrelin values following diet-induced weight loss are associated with loss of fat-free mass, but not with changes in fat mass, insulin levels or insulin sensitivity

Objective: To determine which parameters of body composition or metabolism best correlate with changes in 24 h ghrelin levels following weight loss. Design: A 3-month low-calorie diet followed by 3 months of weight stabilization. Subjects: Twelve overweight and obese adult men and women. Measurements: Body composition by underwater weighing, abdominal fat depots, leptin, ghrelin and parameters of insulin and lipid metabolism. Results: Increased 24 h ghrelin levels after weight loss correlated with decreases in body mass index, subcutaneous fat and fat-free mass (FFM), but not with changes in fat mass, fat cell size, leptin, insulin, insulin sensitivity, lipids or free fatty acid levels. The change in FFM correlated with the rise in ghrelin levels independently of body adiposity. Discussion: Alterations in FFM with diet-induced weight loss may play a role in ghrelin regulation. Changes in ghrelin levels could, then, serve as an integrative signal reflecting changes in FFM to hypothalamic centers controlling energy homeostasis.