title: Effects of Advice to Drink 8 Cups of Water per Day in Adolescents With Overweight or Obesity: A Randomized Clinical Trial.
abstract: Health care professionals commonly recommend increased water consumption, typically to 8 cups per day, as part of a weight-reducing diet. However, this recommendation is based on limited evidence and virtually no experimental data from the pediatric population.
  
  
  
  To compare 2 standardized weight-loss diets among adolescents with overweight or obesity, either with or without additional advice and behavioral support to increase habitual water intake to 8 cups per day.
  
  
  
  A randomized clinical, parallel-group trial was conducted between February 2, 2011, and June 26, 2014, at Boston Children's Hospital, Boston, Massachusetts, among 38 adolescents with overweight or obesity who reported drinking 4 cups or less of water per day.
  
  
  
  All participants in both groups received similar weight-reducing interventions, differentiated by advice about water intake (the water group received advice to increase water intake to 8 cups per day; the control group did not receive such advice) but controlled for other dietary recommendations and treatment intensity. The interventions included dietary counseling, daily text messages, and a cookbook with health guides. To support adherence to 8 cups of water per day, the water group received well-defined messages about water through counseling and daily text messages, a water bottle, and a water pitcher with filters.
  
  
  
  The primary outcome was 6-month change in body mass index z score. Data analyses followed the intention-to-treat principle.
  
  
  
  All 38 participants (27 girls and 11 boys; mean [SD] age, 14.9 [1.7] years) completed the study. Both groups reported drinking approximately 2 cups of water per day at baseline. Self-reported change in water intake at 6 months was greater in the water group (difference from baseline, 2.8 cups per day [95% CI, 1.8 to 3.8]; P < .001) compared with that in the control group (difference from baseline, 1.2 cups per day [95% CI, 0.2 to 2.2]; P = .02) (difference between groups, 1.6 cups per day [95% CI, 0.2 to 3.0 cups per day]; P = .03). The 6-month change in body mass index z score did not differ between the water group (difference from baseline, -0.1 [95% CI, -0.2 to -0.0]; P = .005) and the control group (difference from baseline, -0.1 [95% CI, -0.2 to -0.0]; P = .008) (difference between groups, -0.0 [95% CI, -0.1 to 0.1]; P = .88).
  
  
  
  Advice and behavioral supports to consume 8 cups of water per day in the context of a weight-reducing diet did not affect body weight among adolescents with overweight or obesity. Despite intensive behavior supports, few adolescents achieved the target of 8 cups of water per day. Environmental interventions to reduce barriers to water consumption at school may be necessary in future research of the feasibility and effectiveness to achieve the target of an intake of 8 cups of water per day in adolescents.
  
  
  
  clinicaltrials.gov Identifier: NCT01044134.
authors.affiliation: New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, Massachusetts2Clinical Nutrition and Risk Factor Modification Center, St Michael's Hospital, Toronto, Ontario, Canada3now also with Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Julia M W
authors.initials: JMW
authors.lastname: Wong
authors.affiliation: New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Cara B
authors.initials: CB
authors.lastname: Ebbeling
authors.affiliation: New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, Massachusetts4now with Shape Up Somerville, Somerville, Massachusetts.
authors.forename: Lisa
authors.initials: L
authors.lastname: Robinson
authors.affiliation: Clinical Research Center, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: Henry A
authors.initials: HA
authors.lastname: Feldman
authors.affiliation: New Balance Foundation Obesity Prevention Center, Boston Children's Hospital, Boston, Massachusetts.
authors.forename: David S
authors.initials: DS
authors.lastname: Ludwig
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D003376:Counseling; D004038:Diet, Reducing / Q000379:methods*; D060766:Drinking Water; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts; D009765:Obesity / Q000178:diet therapy*; D050177:Overweight / Q000178:diet therapy*; D014867:Water
chemical_list: D060766:Drinking Water; D014867:Water