Daily stressors, past depression, and metabolic responses to high-fat meals: A novel path to obesity

Background Depression and stress promote obesity. This study addressed the impact of daily stressors and a history of major depressive disorder (MDD) on obesity-related metabolic responses to high-fat meals. Methods This double-blind, randomized, crossover study included serial assessments of resting energy expenditure (REE), fat and carbohydrate oxidation, triglycerides, cortisol, insulin, and glucose before and after two high-fat meals. During two separate 9.5-hour admissions, 58 healthy women (38 breast cancer survivors and 20 demographically similar control subjects), mean age 53.1 years, received either a high saturated fat meal or a high oleic sunflower oil meal. Prior day stressors were assessed by the Daily Inventory of Stressful Events. Results Greater numbers of stressors were associated with lower postmeal REE (p = .008), lower fat oxidation (p = .04), and higher insulin (p = .01), with nonsignificant effects for cortisol and glucose. Women with prior MDD had higher cortisol (p = .008) and higher fat oxidation (p = .004), without significant effects for REE, insulin, and glucose. Women with a depression history who also had more stressors had a higher peak triglyceride response than other participants (p = .01). The only difference between meals was higher postprandial glucose following sunflower oil compared with saturated fat (p = .03). Conclusions The cumulative 6-hour difference between one prior day stressor and no stressors translates into 435 kJ, a difference that could add almost 11 pounds per year. These findings illustrate how stress and depression alter metabolic responses to high-fat meals in ways that promote obesity.