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

Abstract

Objective: To investigate the efficacy of water preloading before meals as a weight loss strategy for adults with obesity. Methods: A two-group randomized controlled trial was conducted in Birmingham, England. Eighty-four adults with obesity were recruited from general practices. All participants were given a face-to-face weight management consultation at baseline (30 min) and a follow-up telephone consultation at 2 weeks (10 min). At baseline, participants were randomized to either drinking 500 ml of water 30 min 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-week follow-up. Several measures of adherence were also used, including 24 h total urine collections. Results: 41 participants were randomized to the intervention group and 43 to the comparator group. The water preloading group lost 21.3 kg (95% CI 22.4 to 20.1, P 5 0.028) more than comparators at follow up. Adjusting for ethnicity, deprivation, age, and gender resulted in the intervention group losing 21.2 kg (95% CI 22.4 to 0.07, P 5 0.063) more than the comparator. Conclusions: There is preliminary evidence that water preloading before main meals leads to a moderate weight loss at follow up. ISRCTN33238158

Inadequate Hydration, BMI, and Obesity Among US Adults: NHANES 2009-2012

“…8 Although these crosssectional studies of water intake and obesity have shown mixed results, results from recent longitudinal studies and randomized controlled trials indicate the potential for water to prevent and treat obesity effectively. 4,9 Findings from 3 prospective cohort studies (the Nurses' Health Study I and II, and the Health Professionals Follow-Up Study) indicate that greater water intake is inversely associated with weight gain. 10 Among these studies, water intake has been the outcome of interest.…”

“…10 Among these studies, water intake has been the outcome of interest. 4,[8][9][10] Urine osmolality, however, is a more effective measure of hydration than water intake alone, as it accounts for water and solutes acquired in food and other beverages. 11 Urine osmolality also measures daily water intake more accurately because it is an objective laboratory measurement that is not subject to recall bias.…”

“…2,3 In addition to replacing sugar-sweetened beverages with water, improving overall hydration is a strategy commonly used to prevent overeating, with the goal of promoting a healthy weight among patients. [4][5][6] For example, counseling patients to first drink water when they have the urge to eat, as they may actually be thirsty rather than hungry, is a recommendation clinicians give patients and is advice readily found in lay media.Water intake as a weight loss tool, however, is not an evidence-based recommendation. Recent studies have shown mixed results, likely because of limitations in the measurement of hunger and thirst, as well as the numerous social, cognitive, sensory, and logistical factors that influence eating and drinking behaviors.…”

“…4,9 Findings from 3 prospective cohort studies (the Nurses' Health Study I and II, and the Health Professionals Follow-Up Study) indicate that greater water intake is inversely associated with weight gain.…”

“…4,[8][9][10] Urine osmolality, however, is a more effective measure of hydration than water intake alone, as it accounts for water and solutes acquired in food and other beverages.…”