Twenty-four-hour ghrelin is elevated after calorie restriction and exercise training in non-obese women

The purpose of this study was to determine whether chronic energy deficiency achieved with caloric restriction combined with exercise is associated with changes in the 24-hour profile of ghrelin in non-obese, pre-menopausal women.

Twelve non-obese (BMI = 18 to 25 kg/m(2)), non-exercising women (age, 18 to 24 years) were randomly assigned to a non-exercising control group or a diet and exercise group. The 3-month diet and exercise intervention yielded a daily energy deficit of -45.7 +/- 12.4%. Serial measurements were made of body composition, energy balance, and feelings of fullness. Repeated blood sampling over 24 hours to measure ghrelin occurred before and after the study.

Significant decreases in body weight, body fat, and feelings of fullness were observed in only the energy-deficit group (p < 0.05); significant changes in the following ghrelin features were found in only the deficit group (p < 0.05): elevations in baseline (+353 +/- 118 pg/mL), lunch peak (+370 +/- 102 pg/mL), dinner peak (+438 +/- 149 pg/mL), nocturnal rise (+269 +/- 77 pg/mL), and nocturnal peak (+510 +/- 143 pg/mL). In addition, we found a larger dinner decline (-197 +/- 52 pg/mL) and negative correlations between changes in the ghrelin dinner profile and changes in body weight (R = 0.784), 24-hour intake (R = 0.67), energy deficiency (R = 0.762), and feelings of fullness (R = 0.648; p < 0.05).

Changes in ghrelin concentrations across the day after weight loss are closely associated with other physiological adaptations to energy deficiency, further supporting the role of ghrelin as a countermeasure to restore energy balance.