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.
Effects of a controlled trial of a school-based exercise program on the obesity indexes of preschool children.
Exercise has been found to be effective for prevention of weight gain and maintenance of a stable weight in adults. The objective of this study was to evaluate the effect of a school-based aerobic exercise program on the obesity indexes of preschool children. Subjects were 292 second-year elementary school pupils from 2 kindergartens in Hat Yai municipality, Songkhla province, southern Thailand. A specially designed exercise program, including a 15-min walk before beginning the morning class and a 20-min aerobic dance session after the afternoon nap, 3 times a week, was conducted for 29.6 wk. Weight, height, and triceps skinfold thickness were measured 4 times. At the end of the study, the prevalence of obesity, using 95th percentile National Center for Health Statistics triceps-skinfold-thickness cutoffs, of both the exercise and control groups decreased. That of the exercise group decreased from 12.2% at baseline to 8.8% (Wilcoxon signed-rank test, P = 0.058), whereas that of the control group decreased from 11.7% to 9.7% (Wilcoxon signed-rank test, P = 0.179). A sex difference in the response of body mass index (BMI) to exercise was observed. Girls in the exercise group had a lower likelihood of having an increasing BMI slope than the control girls did (odds ratio: 0.32; 95% CI: 0.18, 0.56). In conclusion, our study suggests that a 29.6-wk school-based exercise program can prevent BMI gain in girls and may induce a remission of obesity in preschool-age children.