Supplementary Material for: The anti-lipolytic effect of insulin in adipocytes associates with the magnitude of dietary induced weight loss: a longitudinal study

BACKGROUND: Insulin resistance is prominent in overweight/obesity. We examined if insulin action in fat cells predicts the outcome of therapeutic weight loss
METHODS: We investigated 93 adult Swedes with overweight/obesity (body mass index, BMI, 29-50 kg/m2) before and after hypo-energetic high- or low-fat diet for 10 weeks. At baseline overall insulin resistance (homeostasis model assessment, HOMA-IR), and insulin action on lipolysis and lipogenesis in isolated abdominal subcutaneous fat cells were determined. The participants were divided into tertiles based on their values for the cellular insulin action parameters. The relationship to weight loss (kg body weight, kg body fat or BMI) was examined by analysis of variance. The influence of baseline age, sex, waist-to-hip ratio, physical activity, BMI, height and body weight were investigated by analysis of covariance. Because the body weight loss (on average 8 kg) did not differ between the diets their respective data were combined.
RESULTS: HOMA-IR, the maximum insulin induced anti-lipolysis or lipogenesis, and the sensitivity (half-maximum effective hormone concentration) of the lipogenesis effect did not associate with weight loss (F=0.1-1.7: p=0.19-0.96). However, all weight loss parameters associated with insulin sensitivity of anti-lipolysis (F=3.1-4.2; p=0.019-0.0495). Body weight loss was about 30% greater in those with highest compared with lowest anti-lipolytic insulin sensitivity, which was independent of the co-factors mentioned above (F=2.9-3.1; p=0.003-0.005).
CONCLUSION: A high anti-lipolytic insulin sensitivity in subcutaneous fat cells independently associates with pronounced weight loss following energy-restricted diet, whereas lipogenesis and overall insulin resistance are not related to weight change.