Diabetes mellitus and weight control: Differences of respiratory quotient in type 2 diabetic obese subjects receiving sulfonylureas and non-diabetic obese controls

The benefit of weight loss in type 2 diabetes has been recognized since the early 1940s.2 A significant reduction in morbidity and mortality was found after moderate weight loss in these patients.3 Most medium- to long-term studies aiming to induce weight loss in obese type 2 diabetic patients have failed to achieve an acceptable maintenance of weight reduction.4,5 Further, significant weight gains were found in type 2 diabetic patients receiving insulinotropic medications such as sulfonylureas, as demonstrated by the United Kingdom Prospective Diabetes Study.6 The mechanism is still a subject of debate, but the most prominent explanation is the lipogenic effect of insulin. [...]the antilipolytic effect of insulin may contribute to weight gain by reducing levels of free fatty acids and their availability for oxidation.7 Therefore, we investigated possible differences of respiratory quotient (RQ) between obese, type 2 diabetic subjects receiving sulfonylureas and obese, non-diabetic control subjects. In our study RQ was measured in the fasting state 12 h after a standardized dinner. [...]a low RQ (