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.
Two-year follow-up of an obesity prevention initiative in children: the APPLE project.
In a 2-y intervention targeting increased physical activity and healthy eating in primary school children, the adjusted body mass index (BMI) z score was 0.26 units (95% CI: 0.21, 0.32) lower in intervention than in control children. Few obesity prevention initiatives in children have undertaken follow-up analyses.
                The objective was to determine whether differences in BMI persisted approximately 2 y after the cessation of the intervention.
                All children who had at least one measurement of height and weight at any time during the study (baseline and years 1 or 2) were invited to participate in follow-up measurements (height and weight).
                Five hundred fifty-four of 727 eligible children (76%) participated. Children who refused to participate (n = 14) or had moved from the study area (n = 159) did not differ from the remaining participants in baseline age, sex, or BMI. The mean BMI z score (and 95% CI) remained significantly lower in intervention children at follow-up in the whole group (n = 554; -0.17; -0.25, -0.08) and in the group who underwent at least 1 (n = 389; -0.19; -0.24, -0.13) or 2 (n = 256; -0.21; -0.29, -0.14) full years of intervention. Intervention children were less likely to be overweight, but only in those who were present for the full intervention (n = 256; RR: 0.81; 95% CI: 0.69, 0.94).
                Despite the main intervention initiative (school-based activity coordinators charged with the responsibility of enhancing physical activity and promoting healthy eating) being discontinued at the end of the intervention, continued benefits to BMI remained apparent in intervention children approximately 2 y later.