Women with overweight or obesity who maintained at least 15% reduction in body weight for 12 months were more likely to have improved insulin sensitivity when compared with normal-weight women and women with overweight or obesity who regained weight, according to recently published findings.
“Although some studies show sustained improvements in insulin sensitivity with successful weight maintenance at 12- and 18-month follow-up, other studies have shown either continued improvement or a reversal with weight regain,” Jacolene Kroff, PhD, of the division of exercise science and sports medicine at the University of Cape Town, South Africa, and colleagues wrote. “It is, however, unclear whether weight-reduced or weight loss-relapsed individuals eventually return to a level of insulin sensitivity that is in line with phenotypically similar individuals with no history of weight gain and loss, or whether, over the long term, they are metabolically worse off as a result of this weight history.”
Kroff and colleagues analyzed data from healthy women aged 20 to 45 years recruited through the Sport Science Institute of South Africa and other local institutions. Women were screened and stratified by four weight-loss categories: those with BMI at least 27 kg/m² who lost at least 15% of body weight and maintained weight loss for at least 12 months, with a 5% fluctuation from goal body weight over the previous 12 months (n = 15); age-matched, weight-stable controls with BMI 27 kg/m² or lower (n = 19); women with BMI at least 27 kg/m² who previously lost at least 15% of body weight, but subsequently regained all weight lost (n = 11); and age-matched women with overweight or obesity with no weight-loss history (n = 11).
All participants underwent a 75-g oral glucose tolerance test; fasting and 2-hour plasma
glucose and insulin levels were also measured; homeostatic model assessment of insulin resistance and insulin sensitivity index were used to evaluate insulin sensitivity. Participants completed questionnaires and 24-hour dietary recalls and completed treadmill walking tests; physical activity was measured using accelerometers.
Across all four groups, blood glucose levels were comparable after OGTTs, but women with obesity who maintained weight loss had lower fasting and 2-hour insulin levels compared with all other groups (P < .005). When assessing HOMA-IR measurements, women with obesity who maintained 15% weight loss were also more insulin sensitive than weight-stable, normal-weight women; women with obesity who regained weight; and women with obesity and no weight-loss history (mean, 0.85 vs. 1.86, 2.36 and 3.1, respectively; P < .001 for all comparisons).
Using beta coefficients, the strongest predictors of insulin sensitivity were percentage of body weight lost (beta = 0.612), followed by body weight regained (beta = 0.6) and respiratory quotient ratio (–0.231), according to the researchers.
“What is remarkable is that women in the [obesity/weight-loss group] had maintained substantial weight loss of around 15% for a lengthy period (median, 30 months) and yet were found to be more insulin sensitive relative to phenotypically similar, age- and BMI-matched controls with no weight-loss history,” the researchers wrote. “There were no significant differences in metabolic rate, substrate utilization or dietary intake that might explain the lower insulin resistance in this group, besides a modest engagement in vigorous activity.”
The researchers noted that weight-loss maintenance programs should be emphasized after substantial weight loss to retain metabolic benefits. – by Regina Schaffer
The researchers report no relevant financial disclosures.