WHY DRINK WATER

drinking water stations in cafeterias to significantly reduce the risk of overweight and obesity for millions of children [2]. Conditions that may modify drinking water effects include characteristics of the target population at baseline, normal, or overweight/obese status; ad libitum or restricted diet; amount and types of beverages consumed; and hydration status (concentrated or dilute urine). Under ad-libitum diet conditions, interventions to promote drinking water instead of other beverages (i.e., to increase drinking water in relative terms) have been effective when drinking water replaces all caloric beverages, not only sugar-sweetened beverages. Under restricted diet conditions, interventions to increase drinking water in absolute terms have been effective for overweight or obese individuals, if the volume of drinking water consumed significantly dilutes urine [below 500 millimoles per kilogram (mmol/kg)]. In New York City schools, the baseline prevalence of overweight or obesity was 39%, the children had access to ad-libitum food, and the background availability of caloric beverages was deliberately limited, such that drinking water replaced caloric beverages, beyond only sugar-sweetened beverages. Beginning in 2001, New York City implemented policies to remove soda from school vending machines, replace whole milk with low-fat milk in school meals, and limit available beverages to those with less than 10 calories per 8oz serving. All schools made these changes before 2009-2010, before installation of drinking water stations. After installation of the water stations in 2010-2013, purchases of fat-free chocolate milk decreased significantly [2]. To create and sustain conditions, collective impact partnerships are necessary, such as change in school policy, food supply/vendor contracts, and/or funding streams. Also necessary is the development of consistent intervention messaging in the community, tailored to the population characteristics. Alone, individuals trying to drink water for weight management, or

"Drinking water stations in New York City school cafeterias are associated with significantly reduced risk of overweight and obesity for millions of children." clinicians advising patients to drink water for weight management, do not have the authority or control over communitywide background conditions. Null effects of effort to drink water for health outcomes disappoint individuals who make the effort, leave at-risk individuals at-risk, breed uncertainty about drinking water effects, and jeopardize community support and sustainability for drinking water efforts. Industry commitment to, and participation in, collective impact efforts to create optimal conditions for drinking water effects may enable communities, around the world, to benefit from drinking water.

Jodi D Stookey, PhD, is a clinical scientist at the Children’s Hospital Oakland Research Institute.

References 1. Stookey JD. Negative, Null and Beneficial Effects of Drinking Water on Energy Intake, Energy Expenditure, Fat Oxidation and Weight Change in Randomized Trials: A Qualitative Review. Nutrients. 2016 Jan; 8(1): 19. Published online 2016 Jan 2. doi: 10.3390/nu8010019. 2. Schwartz AE, Leardo M, Aneja S, Elbel B. Effect of a School-Based Water Intervention on Child Body Mass Index and Obesity. JAMA Pediatr. 2016 Mar; 170(3): 220–226. doi: 10.1001/ jamapediatrics.2015.3778.

JAN/FEB 2017

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