Relationship of insulin dynamics to body composition and resting energy expenditure following weight loss.

Abstract

ObjectiveTo examine associations of baseline insulin dynamics with changes in body composition and resting energy expenditure (REE) following weight loss.MethodsTwenty-one participants with overweight or obesity achieved 10-15% weight loss and then received 3 weight-loss maintenance diets (high-carbohydrate, moderate-carbohydrate, low-carbohydrate) in random order, each for 4 weeks. Body composition was measured at baseline and after weight loss. Insulin 30 minutes after glucose consumption (insulin-30; insulin response), C-peptide deconvolution analysis, HOMA, hepatic insulin sensitivity (IS), and REE were assessed at baseline and after each maintenance diet.ResultsInsulin-30, but not maximal insulin secretion, hepatic IS or HOMA, predicted changes in fat mass (standardized β=0.385, 1.7 kg difference between 10th-90th centile of insulin-30, P=0.04) after weight loss. Insulin-30 (β=−0.341, −312 kcal/d, P=0.008), maximal insulin secretion (β=−0.216, −95 kcal/d, P=0.0002), HOMA (β=−0.394,−350 kcal/d, P=0.002) and hepatic IS (β=0.217, 225 kcal/d, P=0.0003) predicted change in REE during weight-loss maintenance, independent of changes in body composition. The inverse relationship between insulin-30 and REE was substantially attenuated when the low-carbohydrate diet was consumed first.ConclusionsThese findings distinguish a novel phenotype, characterized by high insulin response, at risk for weight regain, and identify a dietary approach to ameliorate this risk.