Intervention studies conducted in non-school-based settings: The literature on interventions that take place in settings other than schools is sparse. We need more studies that test environmental and policy-based interventions. Also, very few preventive studies took place in clinical settings such as in primary care practices. Primary healthcare providers could play an important role in childhood obesity prevention by providing healthful eating and exercise guidelines to children and their parents, as well as by regularly monitoring body weight.
Innovative study design and intervention approaches: Drawing upon established behavioural theories and strategies when designing interventions may help researchers increase their success in childhood obesity prevention. For example, only a few studies used social marketing to inform the delivery of messages on nutrition, PA and health. Studies may integrate this approach with other intervention components to promote healthful lifestyle changes. Consumer health informatics may have promise. However, only seven studies used consumer health informatics in our study and only one significantly reduced obesity risk.
Systems science-guided intervention studies: Obesity is the result of a complex mix of biological, behavioural, social, economic and environmental factors. An effective and sustainable strategy for obesity prevention may have to target many factors. Applying a systems science approach in intervention design, implementation and evaluation can take into account multiple risk factors as well as the complex interactions and feedback loops between them.
Potential differential effects of interventions across subgroups: Research into population subgroups (e.g. given gender, age, race/ethnicity or socioeconomic status) and the potentially different responses across groups to the same intervention may help tailor and target future interventions to maximize beneficial impacts. Most of the studies included in this review did not report their results by population subgroup.
Programmes of greater statistical power: Interventions with larger sample sizes and lengthier follow-up are important. Most of the interventions we reviewed resulted in modest behavioural changes. Many factors can potentially affect individual dietary and PA behaviours so the study sample or follow-up time may not be sufficiently large or long enough for an intervention’s impact to be seen.
Publication of intervention process evaluation results: Publication of process evaluation results from the intervention’s implementation should be encouraged. Such knowledge is important to carry out translational research and for the scaling up of public health interventions. Very few of the studies we reviewed here reported process evaluation results. Future studies may consider building in process evaluation during the intervention design, data collection and final analysis stages.
Application of rigorous analytical approaches: More rigorous analytical approaches are needed to better analyse repeated measures often collected during longer term follow-up periods, to control for potential confounding variables remaining after randomization and to test for effect modification and heterogeneity in the treatment or intervention effect.
Assessment of the intervention cost-effectiveness: Although challenging, cost-effectiveness analyses will add important value to an intervention’s evaluation. Such information is also important for the promotion and dissemination of effective interventions as well as for informing policymakers’ decisions. Very few studies reported obesity prevention programme costs.
Obesity prevention research in adolescents: Obesity in adolescents has been found to be more predictive of obesity during adulthood than obesity in younger children. Adolescence is an important stage of life when young people are exposed to various social and environmental factors that establish lifelong life habits. Although studies examined in this review included children aged 2–18, analyses could not be limited to teens as results were not reported in this manner. As recommended earlier, subgroup-oriented research may offer in-depth information on obesity prevention important to consider for this life stage.
Potential harms: The implementation of intervention programmes may also have potential harms, such as inciting stigma when implemented on a large scale to many children but to little or no effects (as was observed with most studies included in our review). Children enrolled in obesity prevention programmes are weighed and/or measured and may anticipate improvements. If no significant improvements (or benefits) were observed, some may feel a sense of failure or lowered self-esteem. Although we did not see evidence of this in the studies we reviewed, future research is needed to examine this issue more in-depth.
