Breakthrough in fight against childhood obesity

What children eat has a greater influence than physical activity on their body weight, a Deakin University study has found.

The results of the study, published in The American Journal of Clinical Nutrition, also offers a major breakthrough by providing a simple formula for predicting the effects on body weight of changes in diet or physical activity. This will be vital for assessing the potential of various programs to prevent obesity in children and adolescents.

Deakin researchers used data pooled from studies of more than 900 children aged 4-18 years around the world. They found that, even after they had accounted for differences in age, height and gender, there was still a large variation in their body weights and that three-quarters of this variation could be explained by the heavier children eating more.

“This suggests that it is overeating that is the major driver in the childhood obesity epidemic,” said Professor Boyd Swinburn professor of population health and head of Deakin University’s World Health Collaborating Centre for Obesity Prevention. “This fits with the last two national nutrition surveys which showed a 13 percent increase in energy intake in children over 10 years, mainly due to an increase in junk food consumption.”

Many countries, including Australia, are grappling with how to turn the tide on childhood obesity. Predicting which programs are likely to be most effective has proven problematic because until now it has not been possible to estimate the effects of changes in diet or physical activity on changes in body weight.

“The simple formula we derived in this study allows us to make predictions of the effectiveness of obesity prevention programs,” Professor Swinburn explained. “For example, if programs to get children to switch from energy dense foods, like high fat snacks, to fruit and vegies reduced their energy intake by 10 percent, they would weigh, on average, 4.5 percent less as a result.

“Accurately modelling the effectiveness of various population interventions will provide public health decision makers with an important interim guide to investment in obesity prevention while they await more empirical weight-change studies in children and adolescents.”

Professor Swinburn’s formula is already being applied in Victoria where the Department of Human Services is currently funding an assessment of the cost-effectiveness of several potential interventions to reduce childhood obesity.