Successful, long-term maintenance of weight loss tied to enhanced insulin sensitivity
Women with successful weight loss and who subsequently maintain their reduced weight for extended periods of time are more insulin sensitive compared with their body mass index (BMI)-matched counterparts with no history of weight loss, a study has found. This particular association is independent of dietary intake and physical activity.
The study included 56 women aged 20 to 45 years who were grouped into four as follows: (1) successfully reduced individuals, having previously lost ≥15 percent of their body weight (BW) from a BMI ≥27 kg m−2 and maintained this for over 12 months with ≤5 percent fluctuation from goal BW over the previous 12 months (RED; n=15); (2) age-matched, stable low-weight controls with a BMI ≤27 kg m−2 but with no prior weight loss history (LSW; n=19); (3) weight-relapsed individuals with a BMI ≥27 kg m−2, having previously lost ≥15 percent of their BW but subsequently regained all of this weight (REL; n=11); and (4) age-matched, overweight and obese stable weight (OSW) controls with a BMI ≥27 kg m−2 but no weight-loss history (OSW; n=11).
Fasting and 2-hour plasma glucose and insulin were determined using a 75 g oral glucose tolerance test. Homeostatic Model Assessment (HOMA-IR) and insulin sensitivity index were used to evaluate insulin sensitivity. Other assessments included anthropometric measurements, fasting resting metabolic rate (RMR) and respiratory quotient (RQ). Questionnaires and dietary intake were recorded, and physical activity was determined using accelerometers.
Results showed that insulin sensitivity was more enhanced in the RED group vs all other groups, having lower fasting (p=0.001) and 2-hour insulin (p=0.003). No significant differences were seen in dietary intake, sedentary, light and moderate activity, RMR or RQ in the RED group vs the other three groups.
In multiple linear regression models, percentage of BW lost (p<0.001), percentage of BW regained (p<0.05), body fat percentage, light activity (p<0.05, only log HOMA), vigorous activity (p<0.05) and RQ (p<0.01) predicted 61.4 and 59.7 percent of variability in log HOMA and in log insulin sensitivity index, respectively.
The findings indicate that successful weight loss maintainers achieve sustained enhanced insulin compared with BMI-matched controls with no weight loss history. With weight loss relapse, such metabolic benefits can no longer be seen. Weight loss itself is the strongest predictor of improved insulin sensitivity, whereas weight regain significantly predicts reduced insulin sensitivity, researchers said.
“Weight-loss maintenance programmes are essential to retaining metabolic benefits acquired through weight loss,” they added.