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.
School randomised trial on prevention of excessive weight gain by discouraging students from drinking sodas.
To determine whether an educational programme aimed at discouraging students from drinking sugar-sweetened beverages could prevent excessive weight gain.
                Forty-seven classes in twenty-two schools were randomised as intervention or control.
                Participants were 1140, 9-12-year-old fourth graders (435 in the intervention group and 608 in the control group). Sugar-sweetened beverages and juice intake were measured through one 24 h recall at baseline and another at the end of the trial. The main outcome was the change in BMI (BMI = weight (kg)/height (m2)), measured at the beginning and at the end of the school year. Intention-to-treat analysis was performed taking into account the cluster (classes) effect.
                A statistically significant decrease in the daily consumption of carbonated drinks in the intervention compared to control (mean difference = -56 ml; 95 % CI -119, -7 ml) was followed by a non-significant overall reduction in BMI, P = 0.33. However, among those students overweight at baseline, the intervention group showed greater BMI reduction (-0.4 kg/m2 compared with -0.2 kg/m2 in the control group (P = 0.11)), and this difference was statistically significant among girls (P = 0.009). Fruit juice consumption was slightly increased in the intervention group (P = 0.08), but not among girls.
                Decreasing sugar-sweetened beverages intake significantly reduced BMI among overweight children, and mainly among girls. Efforts to reduce energy intake through liquids need to emphasise overall sweetened beverages and addition of sugar on juices.