Effects of metformin on energy intake and satiety in obese children

Aims: To investigate the effects of metformin on appetite and energy intake in obese children with hyperinsulinaemia. Methods: We conducted a 6-month randomized, double-blind, placebo-controlled trial to evaluate the effects of metformin 1000 mg twice daily on body weight and energy balance in 100 obese children with hyperinsulinaemia aged 6-12 years. The children ate ad libitum from standardized food arrays on two separate occasions before and after 6 months of study medication. The first test meal was consumed after an overnight fast. The second was preceded by a pre-meal load. For each test meal, energy intake was recorded, and the children completed scales of hunger, fullness and desire to eat. Results: Data from the meal studies at baseline and after treatment with study medication were available for 84 children (metformin-treated, n=45; placebo-treated, n=39). Compared with placebo, metformin treatment elicited significant reductions from baseline in adjusted mean +/- standard error of the mean energy intake after the pre-meal load (metformin: -104.7 +/- 83.8 kcal vs. placebo: +144.2 +/- 96.9 kcal; p=0.034) independently of changes in body composition. Metformin also significantly decreased ratings of hunger (-1.5 +/- 5.6 vs. +18.6 +/- 6.3; p=0.013) and increased ratings of fullness (+10.1 +/- 6.2 vs. -12.8 +/- 7.0; p=0.01) after the pre-meal load. Conclusions: These data suggest that decreased perceived hunger resulting in diminished food intake are among the mechanisms by which metformin treatment reduces body weight in overweight children with hyperinsulinaemia.