Background and aim: Disturbances in cortisol metabolism have been associated with obesity and metabolic syndrome development. The aim of this study was to evaluate the effect of weight loss induced by an energy-restricted diet on postprandial cortisol secretion in obese men with and without metabolic syndrome features.
Methods and results: Twelve obese men (BMI: 32.5-36.2 kg/m2), six without and six with at least three markers of metabolic syndrome, and six lean men (BMI: 22.2-24.9 kg/m2) participated. Plasma cortisol was measured at fasting and at 30 min intervals for 3h after standard breakfast intake. Obese volunteers repeated those measurements after weight loss induced by a 10-week hypocaloric balanced diet. Fasting (p = 0.002) and postprandial (p = 0.014) cortisol secretions in obese men were statistically lower than in lean subjects. The slimming program produced a -0.9 kg per week mean weight reduction with no differences between both groups (p = 0.297). After weight loss, postprandial cortisol secretion increased in volunteers with (p = 0.028) and without metabolic syndrome manifestations (p = 0.043), as compared to baseline, achieving values near to those of controls. Cortisol levels negatively correlated with body weight (r = -0.61; p < 0.001).
Conclusions: Therefore, the effect of weight loss on cortisol metabolism appeared to be mediated by changes in body weight, which were apparently not affected by the occurrence of metabolic syndrome features.