We found strong evidence to support beneficial effects of child obesity prevention programmes on BMI, particularly for programmes targeted to children aged six to 12 years. However, given the unexplained heterogeneity and the likelihood of small study bias, these findings must be interpreted cautiously. A broad range of programme components were used in these studies and whilst it is not possible to distinguish which of these components contributed most to the beneficial effects observed, our synthesis indicates the following to be promising policies and strategies:
·         school curriculum that includes healthy eating, physical activity and body image
·         increased sessions for physical activity and the development of fundamental movement skills throughout the school week
·         improvements in nutritional quality of the food supply in schools
·         environments and cultural practices that support children eating healthier foods and being active throughout each day
·         support for teachers and other staff to implement health promotion strategies and activities (e.g. professional development, capacity building activities)
·         parent support and home activities that encourage children to be more active, eat more nutritious foods and spend less time in screen based activities
However, study and evaluation designs need to be strengthened, and reporting extended to capture process and implementation factors, outcomes in relation to measures of equity, longer term outcomes, potential harms and costs.
Childhood obesity prevention research must now move towards identifying how effective intervention components can be embedded within health, education and care systems and achieve long term sustainable impacts.
Prevention of obesity--more than an intention. Concept and first results of the Kiel Obesity Prevention Study (KOPS).
Obesity prevention is necessary to address the steady rise in the prevalence of obesity. Although all experts agree that obesity prevention has high priority there is almost no research in this area. The effectiveness of different intervention strategies is not well documented. There is also no structured framework for obesity prevention.
                Based on (i) our current and limited knowledge and (ii) the idea that prevention of childhood obesity is an effective treatment of adult obesity, the Kiel Obesity Prevention Study (KOPS) was started in 1996. Concept, intervention strategies and first results of KOPS are reported in this paper. KOPS is an ongoing 8 y follow-up study. We first enrolled a large scale cohort of 5 to 7-y-old children, providing sufficient baseline data. KOPS allows further analyses of the role of individual risk factors as well as of long-term effectiveness of different intervention strategies.
                From 1996 to 1999 a representative group of 2440 5 to 7-y-old children was recruited (ie 30.2% of the total population of 5 to 7-y-old children examined by the school physicians) and a full data set was obtained from 1640 children. Of the children, 340 (20.7%) were considered as overweight and obese, 1108 children (67.6%) were normal weight, and underweight was found in 192 children (11.7%). Of the normal-weight children, 31% or 346 (21.1% of the total population) were considered to have a risk of becoming obese. Cross-sectional data provided evidence that (i) there is an inverse social gradient in childhood overweight as well as health-related behaviours and (ii) parental fatness had a strong influence on childhood overweight. We observed considerable changes in health-related behaviours within 1 y after combined "school-" and "family-based" interventions. Interventions aimed to improve health-related behaviours had significant effects on the age-dependent increases in median triceps skinfolds of the whole group (from 10.9 to 11.3 mm in "intervention schools" vs from 10.7 to 13.0 mm in "control schools", P<0.01) as well as in percentage fat mass of overweight children (increase by 3.6 vs 0.4% per year without and with intervention, respectively; P<0.05).
                First results of KOPS are promising. Besides health promotion, a better school education and social support seem to be promising strategies for future interventions.