Beyond the randomised controlled trial and BMI – evaluation of effectiveness of through-school nutrition and physical activity programmes

Abstract

Invited Commentary – Evidence has been slow to accumulate that school physical activity and nutrition interventions are effective at slowing the rate of physical growth and reducing the prevalence of obesity in children. This is in part because of the need for randomised controlled trials (RCT) that meet strict quality criteria. In addition, the focus on BMI-for-age criteria to define obesity and overweight, and therefore the outcome of ‘effective’ interventions, is a pragmatic measure but may be flawed in that the child’s nutritional and functional status may have improved but BMI may not change. For a population, BMI is a measure of energy balance; it is not a measure of the many other factors that are required for optimal growth, development and function. In this commentary we describe a large-scale intervention utilizing an alternative measure of programme effectiveness. We believe the model and measure can be applied in different contexts to evaluate effectiveness of a programme to improve health in children in a school setting.