Increased 24-h energy expenditure in type 2 diabetes.

OBJECTIVE: The aim of this study was to determine whether overweight and obese individuals with type 2 diabetes have higher basal and 24-h energy expenditure compared with healthy control subjects before and after adjustment for body composition, spontaneous physical activity (SPA), sex, and age.

RESEARCH DESIGN AND METHODS: Data from 31 subjects with type 2 diabetes and 61 nondiabetic control subjects were analyzed. The 24-h energy expenditure, basal metabolic rate (BMR), and sleeping energy expenditure (EEsleep) between 1:00 a.m. and 6:00 a.m. were measured in whole-body respiratory chambers. Body composition was assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS: No significant differences in unadjusted EEsleep, BMR, and 24-h energy expenditure were observed between the type 2 diabetic group and the control group. After adjustment for fat-free mass (FFM), fat mass, SPA, sex, and age, EEsleep and BMR were, respectively, 7.7 and 6.9% higher in the type 2 diabetic group compared with the control group. This was equivalent to 144 +/- 40 kcal/day (P = 0.001) and 139 +/- 61 kcal/day (P = 0.026), respectively. Adjusted 24-h energy expenditure was 6.5% higher in the type 2 diabetic group compared with the nondiabetic control subjects (2,679 +/- 37 vs. 2,515 +/- 23 kcal/day, P = 0.002). In multiple regression analyses, FFM, fat mass, SPA, and diabetes status were all significant determinants of EEsleep and 24-h energy expenditure, explaining 83 and 81% of the variation, respectively.

CONCLUSIONS: This study confirms reports in Pima Indians that basal and 24-h energy expenditure adjusted for body composition, SPA, sex, and age are higher in individuals with type 2 diabetes compared with nondiabetic control subjects and may be even more pronounced in Caucasians.