Resting energy expenditure in type 2 diabetic patients and the effect of insulin bolus

Resting energy expenditure (REE) plays a critical role in the regulation of body weight, with important implications in type 2 diabetes (T2D). However, the relationships between REE and T2D have not been extensively evaluated. We compared REE in persons with diabetes and in persons without diabetes. We also investigated the acute effect of insulin on REE and venous lactate, the latter an indirect measure of neoglucogenetic activity.

REE was measured using indirect calorimetry in 14 newly diagnosed, untreated T2D adults and in 14 non-diabetic age-, gender- and body mass index-matched persons. The REE and lactate venous concentrations were also measured in a subgroup of 5 T2D patients in the hour following an IV insulin bolus.

The REE normalized for fat-free mass (FFM) was significantly higher in T2D patients than in the group without diabetes (mean ± SD: 27.6 ± 1.9 vs. 25.8 ± 1.9 kcal/kg-FFM·24h; P=0.02). REE normalized for FFM was correlated with fasting plasma glucose concentration (r=0.51; P=0.005). Following the insulin venous bolus REE (0': 2,048 ± 242; 10': 1,804 ± 228; 20': 1,684 ± 230; 30': 1,634 ± 212; 45': 1,594 ± 179; 60': 1,625 ± 197 kcal/24h; P<0.001) and both glucose (P<0.001) and lactate (P<0.001) concentrations progressively declined in the ensuing hour.

Patients with diabetes have a higher energy expenditure, likely a consequence of higher gluconeogenetic activity. This study may contribute to recognizing the nature of body weight reduction that occurs in concomitance with poorly controlled diabetes, and of body weight gain as commonly observed when hypoglycemic treatment is started.