INSULIN SENSITIVITY AS A PREDICTOR OF WEIGHT REGAIN

A recent study found that increases in insulin sensitivity following w eight loss and stabilization were strongly related to subsequent weigh t regain. The present paper analyzed this relationship in two behavior al weight-loss programs. In the first study, 125 nondiabetic subjects were followed over 30 months; weight losses averaged 10 kg at six mont hs, and subjects had regained 8 kg of their weight loss by their 30-mo nth follow-up. Neither fasting insulin levels at six months nor change s in fasting insulin from zero to six months were related to subsequen t weight regain. Similarly, insulin levels measured two hours after a 75 g glucose load were unrelated to subsequent weight regain. The seco nd study followed 33 individuals with Type II diabetes, treated with b ehavior modification, and either a low calorie diet or a very low calo rie diet. Weight losses averaged 18 kg at six months, and subjects had regained 10 kg by their 24-month follow-up. The Bergman minimal model was used to assess insulin sensitivity at 6-month intervals. Initial analyses suggested that changes in insulin sensitivity from zero to si x months were related to subsequent weight regain, but this effect was strongly influenced by an outlier. After removing this individual, th ere were no significant relationships between the changes in insulin s ensitivity that accompanied weight loss and future weight regain. Like wise, insulin sensitivity at 12 months did not predict weight regain f rom 12 to 24 months. These data do not support the hypothesis that inc reases in insulin sensitivity with weight loss are associated with sub sequent weight regain.