Under What Conditions do Water-Intervention Studies Significantly Improve Child Body Weight?

There are particular conditions that may optimize the effects of drinking-water interventions on body weight change and risk of obesity. Strategic planning to create and sustain conditions for optimal effects of drinking water may maximize the impact of school-based interventions to reduce childhood obesity. This paper proposes questions about the target population, type of diet and activity level that will be maintained during the intervention, and planned intervention message(s). The proposed questions are motivated by conditions associated with significant effects of drinking water in randomized controlled trials. They are discussed in relation to conditions underlying the recently successful school-based drinking-water intervention in New York City. If conditions allow, school-based drinking-water interventions have the potential to efficiently benefit millions of children worldwide, who are at risk of becoming obese.