Dairy food consumption and meal-induced cortisol response interacted to influence weight loss in overweight women undergoing a 12-week, meal-controlled, weight loss intervention

Abstract

Dairy food enhances weight loss in animal models, possibly by modifying the metabolic effects of cortisol. This study determined in overweight women (ages 20.0-45.9 y; n = 51) whether including dairy food in an energy-restricted diet affects cortisol concentrations and whether differences in provoked cortisol explain the magnitude of weight loss. Women received either an adequate amount of dairy food (AD), the equivalent of ≤711 mL/d milk, or a low amount of dairy food (LD), theequivalent to ≥238 mL/d milk, in a 12-wk, energy-restricted dietary intervention. Participants were tested in a 12-hlaboratory visit, which included 2 standard meals and a dinner buffet that was consumed ad libitum. Salivary cortisol was measured from waking to bedtime. Energy restriction increased (P ≥ 0.04) the minimum and decreased (P ≥ 0.02) the diurnal amplitude in the salivary cortisol concentration from baseline to postintervention. Energy restriction enhanced the dinner meal- stimulated salivary cortisol response (DMR) (P ≥ 0.02) but only in the LD group. Compared with the LD treatment, the AD treatment induced (P ≥ 0.04) greater reductions in body weight and fat, but only in women characterized as having a baselineDMR(responders) (n = 26);weight and fat lost in the AD and LD groups were similar in nonresponders (n =25).Overall, energy restriction dampened diurnal salivary cortisol fluctuations [symptomatic of hypothalamic-pituitary-adrenal (HPA) axis dysfunction] and enhanced dinner meal-stimulated salivary cortisol concentrations. The AD treatment prevented the latter. Furthermore, certain phenotypic markers of HPA axis function may help to expose the weight-reducing effects of consuming dairy food. © 2013 American Society for Nutrition.