Childhood Obesity Prevention: Changing the Focus

Mary Ann Liebert, Inc. is proud to announce that beginning with Volume 14, Childhood Obesity will increase its offerings to eight issues per year instead of the current six. This will allow us to offer more of the latest in thinking and findings in regard to childhood obesity.

As readers of this journal are readily aware, obesity in the United States ¹ and throughout the world ² remains highly prevalent, especially among children and adolescents. Innumerable child obesity prevention trials emphasizing diet, physical activity, sedentary behavior, and recently sleep have been designed, implemented, and evaluated with the best intentions and the highest hopes. The majority of these interventions have had no or very small effects on adiposity/obesity, ³ but the quality of these studies has been relatively low. ⁴ Some of the largest, more comprehensive, well designed, and well funded trials had no effects on adiposity/obesity.^5,6 Many of the limitations in our existing knowledge base for designing and implementing child obesity prevention programs have been identified as possible reasons explaining these null or modest effects. ⁷ A number of myths in regard to obesity have been addressed and perhaps dispelled. ⁸ Despite the poor record, some have argued that the child obesity prevention research community needs to persist, anticipating that some random variation in an intervention will result in some effectiveness, which can be carried forward and expanded in ensuing iterations. ⁹ Alternatively, a commonly quoted statement attributed to Einstein says “Insanity is doing the same thing over and over again, expecting different results.”

There may be a fundamental problem in our usual approaches. While obesity is almost by definition the result of a long-term imbalance between energy intake and expenditure,^10,11 this simple statement ignores the factors contributing or predisposing to energy imbalance. For example, inadequate energy expenditure could be due to low levels of physical activity or low resting energy metabolism ¹⁰ ; surplus energy intake could be due to inadequate self-control in tempting food environments versus hormonally driven caloric excesses. ¹² Most child obesity prevention behavior change interventions have prescribed a one-size-fits-all behavioral remedy, for example, eat less calories (e.g., less fat) or more lower calorie foods (e.g., fruit and vegetables hoping to displace higher calorie foods) and/or expend more energy (e.g., get more moderate-to-vigorous physical activity) ignoring the biological or other predisposing (moderating effect) factors any one individual may experience.

Usually a subset of the children in the existing trials respond favorably to the intervention, suggesting that these children have the type of obesity that responded well to that prescription, but the others did not. This may indicate many predisposing and contributing factors to childhood obesity, each of which may need/benefit from specific forms of intervention.

Many possible contributors and factors predisposing to childhood adiposity or obesity have been proffered other than dietary overconsumption and inadequate energy expenditure,^13,14 with varying levels of support for each. These include obesogenic infectious agents,^15,16 toxic chemicals, ¹⁷ genetic influences, ¹⁸ epigenetic influences, ¹⁹ the microbiome, ²⁰ brown or beige fat, ²¹ prenatal, ²² and early childhood ²³ factors, just a few among many hypotheses. Theory and research are needed on whether and how these influence the intervention points of energy balance ¹¹ and how they may interact.

Furthermore, predisposing and contributing factors will vary by age. For example, there has been much recent attention to predisposing and contributing factors in the first 1000 days ²² ; parenting is probably more important early in life when a child is more amenable to parental influence, while peers may be more influential in adolescence. ²⁴ Thus, age of the child must be factored into consideration of what are a child's predisposing and contributing factors, and what form of intervention is most likely to be relevant and effective.

In light of these alternative explanations, childhood obesity prevention investigators may want to refocus to incorporate these alternative possible predisposing and contributing factors, including what age(s) they may start or have their major effect and identifying the subgroups of influence. This refocus does not preclude investigation of diet, physical activity, sedentary behavior, and/or sleep, but attempts to clearly identify the subgroups of obesity, or high risk of obesity, in which they operate; the extent to which the predisposing factors interact with one or another of these behaviors to contribute to obesity^11,25; or the subset among whom inadequate self-control really is a primary cause.

With a little luck and lots of effort, this refocus should result in new conceptual and measurement procedures, wherein existing cases of obesity can be attributed to their likely contributing and predisposing factors, and new corresponding triage systems can be generated for applying appropriate targeted and even tailored age and cause specific intervention procedures. Some of these predisposing factors might simply be inadequate access to pleasant activity promoting parks for some subsets of children, but some may require an understanding of the relevant biology. In this light, important broad public health actions might be initiated to mitigate these biological predisposing factors (e.g., vaccines for preventing viral causes or modifications to plastic containers that minimize exposures to endocrine disruptive chemicals, if either were shown to be causally related to adiposity/obesity).

In addition to the innovative but more conventional type articles Childhood Obesity currently publishes, we welcome all well-conceived, adequately powered, rigorously conducted, and carefully analyzed studies, which pursue this alternative focus. Obesity prevention, and perhaps even treatment, intervention investigators face many interesting research possibilities. Sometimes we will pursue investigations with huge payoffs; more often we will not, but when well done those will be important contributions to our science as well.