Evaluation of two dietary treatments in obese hyperinsulinemic adolescents

Hyperinsulinemia increases the risk of cardiovascular disease in obese children. Only a few treatments are available to decrease insulin resistance. The reduction of hyperinsulinemia by dietary means would be a simple, physiologic and economic way to reduce the risk of metabolic disease.

To compare the effects of two low-energy diets on serum insulin concentrations and weight loss in obese hyperinsulinemic adolescents.

Eighty-six randomly assigned insulin-resistant obese adolescents completed a 16 week calorie-restricted diet. The experimental diet had a reduced glycemic index designed to evoke a low insulin response (LIR), with carbohydrates and proteins ingested in separate meals. The control diet was a conventional (CD) with similar proportions (60%, 20% and 20%). Variables studied were blood glucose and insulin concentrations after an oral glucose load, body mass index, waist circumference, and insulin resistance (homeostasis model assessment, HOMA).

Mean weight [+/- Standard Deviation (SD)] was significantly reduced after the LIR (-0.53 +/- 0.5) and the CD (-0.54 +/- 0.4), but a greater decrease of waist circumference (cm) was observed after the LIR (-9.1 +/- 4.8 vs. -6.6 +/- 4.6, p = 0.02). Fasting insulin concentrations (-17.9 +/- 27.9 vs. -9.4 +/- 14.8, p = 0.01) and HOMA dropped significantly more after the LIR than after the CD (-3.5 +/- 4.9SD vs. -2.4 +/- 1SD, p < 0.0001).

The LIR diet reduces serum insulin concentrations and waist circumference more than conventional treatment and appears to be a promising alternative to a conventional diet in insulin-resistant obese adolescents. Long-term follow-up is needed to evaluate the maintenance of weight loss and metabolic parameters.