Context: Endeavours to reduce overweight by calorie-restriction diets are often neither sufficient nor sustained. The growing obesity epidemic demands additional measures to enhance and sustain weight loss.

Objective: To evaluate three alternative weight-loss measures on top of a calorie-restriction diet.

Design, Setting, and Participants: Six-month randomized and controlled trial using a three-factorial design. The participants were 110 families with 142 obese parents and their 119 obese children.

Intervention: All families kept to a calorie-restriction diet and were assigned at random to one or more of three additional weight-loss strategies: (1) a diet on top of calorie-restriction with preference for carbohydrates having a low glycemic index (dual diet), (2) financial incentive, and (3) continuous telemetric control of weight and physical activity (telemonitoring). The design made it possible to determine the effect of each single measure: financial incentive vs. no financial incentive (54 vs.56 families), calorie-restriction vs. dual diet (53 vs. 57 fami-lies) and telemonitoring vs. no telemonitoring (19 vs. 91 families). The design also allowed an assessment of the effects of combinations of the additional measures, each adapted for possible effects of the other factors.

Main Outcome In the parents the outcome variable at 6 months was the relative weight loss. In children, be-cause of their body growth, the outcome variable was the age-adjusted BMI standard deviation score (BMI-SDS). Analysis was done by three-factorial ANOVA and by a one-factorial ANOVA with the included Dunnett test as a post-hoc comparison, to distinguish between the effects of the different combinations of the additional strategies.

Inclusion Criteria:

• BMI > 30 kg/m2

Exclusion Criteria:

• disease of kidney or liver

The participating families were recruited by means of newspaper advertisements in the area around the German city of Magdeburg. The children had to be older than 7 years to ensure that they were able to read, and younger than 13 to minimize interferences due to puberty. 177 families responded by telephone and received a letter de-scribing the aim and character of the study. 110 families then decided to participate and were invited to the first of four meetings with intervals of one week between successive meetings.