Influence of weight loss on plasma ghrelin responses to high-fat and high-carbohydrate test meals in obese women

BACKGROUND: Diet-induced weight loss is associated with an increase in fasting ghrelin. The influence of weight loss on postprandial ghrelin response remains discussed, but the specific response to macronutrients is not known. OBJECTIVE: The objective of the study was to assess the influence of weight loss in obese women on the plasma ghrelin response to a fat- or carbohydrate-rich meal. DESIGN: Seventeen obese women (mean body mass index 37.6 +/- 5 kg/m2) were given an energy-restricted diet (800 kcal/d) for 7 wk, followed by a maintenance diet for 1 wk. Before and after the weight reduction diet, each woman was given (in random order) two isoenergetic test meals, corresponding to 40% of daily energy needs. The test meals contained either 80% fat and 20% protein or 80% carbohydrate and 20% protein. Blood samples were collected over a 10-h period. Two-way ANOVA with repeated measures was used to assess the effect of the test meal on variables. RESULTS: Weight loss (-11.2 +/- 1.4 kg) was associated with a significant decrease in baseline plasma insulin (9.7 +/- 4.1 to 7.9 +/- 2.4 mU/ml; P < 0.0001) and leptin (25.9 +/- 8.3 to 17.2 +/- 7.8 ng/ml; P < 0.0001) and an increase in plasma ghrelin (1.86 +/- 1.05 to 2.28 +/- 1.48 ng/ml; P < 0.05). Before weight loss, there was no significant difference in postprandial ghrelin response between the test meals. After weight reduction, the ghrelin response was more pronounced after the carbohydrate test meal than after the fat test meal (P < 0.02). CONCLUSION: Weight loss is associated with an improved postprandial plasma ghrelin response to a carbohydrate meal, whereas the response to a fat meal is not modified.