Previous research has shown that increased levels of adiposity can lead to increased cortisol response to stress (1, 2, 3). Food intake has also been shown to activate the hypothalamo-pituitary adrenal axis (4, 5) but it is not clear if this activation is influenced by levels of adiposity. We tested the hypothesis that overweight/obese men will have a greater cortisol response to food intake compared to lean men.
Lean (BMI=20-25 kg/m2; n=19) and overweight/obese (BMI=27-35 kg/m2; n=17) men aged 50-70 years were allowed to prepare their own lunch at 12:00 pm using bread, margarine, cheese, processed meat (ham or chicken), tomato, cucumber, nuts, fruit bars and a fruit juice box drink. Records were made of foods consumed. Energy and macronutrient intake were determined using Foodworks (version 6.0; Xyris Software, QLD). Concentrations of cortisol were measured (by enzyme immunoassay) in samples of saliva collected every 15 min from 11:45 am to 2:00 pm with the exception of during lunch (12:15 pm) when no sample was collected.
Overweight/obese men had significantly higher body weight, BMI, percentage body fat and waist and hip circumferences compared to lean men (p < 0.001 for all). The meal consumed by the participants consisted of 22% protein, 53% carbohydrates and 25% fat and did not differ between the groups. For cortisol, repeated measures analysis of variance revealed a significant time*treatment interaction (p=0.008). Overweight/obese men responded to food intake with a significant elevation (51%) in salivary cortisol (time effect: p=0.005) whereas lean men did not have a significant elevation (5%) of cortisol (time effect: p=0.382).While overweight/obese men had a significant cortisol response to food intake, lean men did not. If overweight/obese men have an elevated cortisol response every time they ingest food, they may be more susceptible to the development of stress-related disease.