Efficacy of water preloading before main meals as a strategy for weight loss in primary care patients with obesity: RCT

Research output: Contribution to journalArticlepeer-review

Colleges, School and Institutes

External organisations

  • University of Oxford


Objective: To investigate the efficacy of water preloading before meals as a weight loss strategy for adults with obesity.

Methods: Two group randomized controlled trial conducted in Birmingham, England. 84 adults with obesity were recruited from general practices. All participants were given a face to face weight management consultation at baseline (30 minutes) and a follow-up telephone consultation at two weeks (10 minutes). At baseline participants were randomized to either drinking 500mls of water 30 minutes before their main meals or an attention control group where participants were asked to imagine their stomach was full before meals. The primary outcome was weight change at 12 weeks follow up. Several measures of adherence were also used, including 24hr total urine collections.

Results: 41 participants were randomized to the intervention group and 43 to the comparator group. The water preloading group lost -1.3kg (95% CI -2.4 to -0.1, p=0.028) more than comparators at follow up. Adjusting for ethnicity, deprivation, age and gender resulted in the intervention group losing -1.2kg (95% CI -2.4 to 0.07, p=0.063) more than the comparator.

Conclusion: There is preliminary evidence that water preloading before main meals leads to a moderate weight loss at follow up. ISRCTN33238158


Original languageEnglish
Pages (from-to)1785-1791
Issue number9
Early online date3 Aug 2015
Publication statusPublished - 1 Sep 2015


  • weight loss, clinical trials, primary care, obesity