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.
An intervention to reduce television viewing by preschool children.
Television viewing has been associated with increased violence in play and higher rates of obesity. Although there are interventions to reduce television viewing by school-aged children, there are none for younger children.
                To develop and evaluate an intervention to reduce television viewing by preschool children.
                Randomized controlled trial conducted in 16 preschool and/or day care centers in rural upstate New York.
                Children aged 2.6 through 5.5 years.
                Children attending intervention centers received a 7-session program designed to reduce television viewing as part of a health promotion curriculum, whereas children attending the control centers received a safety and injury prevention program.
                Change in parent-reported child television/video viewing and measured growth variables.
                Before the intervention, the intervention and control groups viewed 11.9 and 14.0 h/wk of television/videos, respectively. Afterward, children in the intervention group decreased their television/video viewing 3.1 h/wk, whereas children in the control group increased their viewing by 1.6 h/wk, for an adjusted difference between the groups of -4.7 h/wk (95% confidence interval, -8.4 to -1.0 h/wk; P =.02). The percentage of children watching television/videos more than 2 h/d also decreased significantly from 33% to 18% among the intervention group, compared with an increase of 41% to 47% among the control group, for a difference of -21.5% (95% confidence interval, -42.5% to -0.5%; P =.046). There were no statistically significant differences in children's growth between groups.
                This study is the first to show that a preschool-based intervention can lead to reductions in young children's television/video viewing. Further research is needed to determine the long-term effects associated with reductions in young children's television viewing.