The aim of the present study was to determine what the difference is of a strong hypo-energetic standard diet advice and a modest hypo-energetic personal diet advice which was determined by the energy needs of a person as calculated with a combination of basal metabolic rate (BMR) and physical activity level (PAL) on weight loss and insulin sensitivity.~Secondly, this study wanted to determine what the influence is of insulin-insensitivity on obesity and weight reduction by treating the patients with metformin or placebo. The subjects were therefore randomised into two double blinded groups receiving either metformin (2 x 850 mg per day) or placebo in combination with a moderate energy restriction and a exercise regimen of 30 minutes per day for 1 year.~Treatment effects of both diets and the effect of metformin on weight reduction and insulin sensitivity were determined after a treatment period of 20 and 52 weeks.~Insulin sensitivity was quantified using the homeostasis model assessment (HOMA) and the OGTT. Body composition was determined with the bioelectrical impedance method.~Blood was also drawn for hormonal and biochemical analyses after 20 and 52 weeks of treatment. Furthermore, the patients had to fill out a 3-day food diary at baseline, after 20 weeks and after 52 weeks.
This is a study to:~Determine the difference between strong hypo-energetic standard diet advice and modest hypo-energetic personal diet advice; and~Determine the influence of insulin-insensitivity on obesity and weight reduction by treating patients with metformin or placebo.