Clive M Brown1, Abdul G Dulloo, Jean-Pierre Montani. 1. Department of Medicine, Division of Physiology, University of Fribourg, Rue du Musée 5, 1700 Fribourg, Switzerland. clivemartin.brown@unifr.ch
Abstract
CONTEXT: A recent study reported that drinking 500 ml of water causes a 30% increase in metabolic rate. If verified, this previously unrecognized thermogenic property of water would have important implications for weight-loss programs. However, the concept of a thermogenic effect of water is controversial because other studies have found that water drinking does not increase energy expenditure. OBJECTIVE: The objective of the study was to test whether water drinking has a thermogenic effect in humans and, furthermore, determine whether the response is influenced by osmolality or by water temperature. DESIGN: This was a randomized, crossover design. SETTING: The study was conducted at a university physiology laboratory. PARTICIPANTS: Participants included healthy young volunteer subjects. INTERVENTION: Intervention included drinking 7.5 ml/kg body weight (approximately 518 ml) of distilled water or 0.9% saline or 7% sucrose solution (positive control) on different days. In a subgroup of subjects, responses to cold water (3 C) were tested. MAIN OUTCOME MEASURE: Resting energy expenditure, assessed by indirect calorimetry for 30 min before and 90 min after the drinks, was measured. RESULTS:Energy expenditure did not increase after drinking either distilled water (P = 0.34) or 0.9% saline (P = 0.33). Drinking the 7% sucrose solution significantly increased energy expenditure (P < 0.0001). Drinking water that had been cooled to 3 C caused a small increase in energy expenditure of 4.5% over 60 min (P < 0.01). CONCLUSIONS: Drinking distilled water at room temperature did not increase energy expenditure. Cooling the water before drinking only stimulated a small thermogenic response, well below the theoretical energy cost of warming the water to body temperature. These results cast doubt on water as a thermogenic agent for the management of obesity.
RCT Entities:
CONTEXT: A recent study reported that drinking 500 ml of water causes a 30% increase in metabolic rate. If verified, this previously unrecognized thermogenic property of water would have important implications for weight-loss programs. However, the concept of a thermogenic effect of water is controversial because other studies have found that water drinking does not increase energy expenditure. OBJECTIVE: The objective of the study was to test whether water drinking has a thermogenic effect in humans and, furthermore, determine whether the response is influenced by osmolality or by water temperature. DESIGN: This was a randomized, crossover design. SETTING: The study was conducted at a university physiology laboratory. PARTICIPANTS: Participants included healthy young volunteer subjects. INTERVENTION: Intervention included drinking 7.5 ml/kg body weight (approximately 518 ml) of distilled water or 0.9% saline or 7% sucrose solution (positive control) on different days. In a subgroup of subjects, responses to cold water (3 C) were tested. MAIN OUTCOME MEASURE: Resting energy expenditure, assessed by indirect calorimetry for 30 min before and 90 min after the drinks, was measured. RESULTS: Energy expenditure did not increase after drinking either distilled water (P = 0.34) or 0.9% saline (P = 0.33). Drinking the 7% sucrose solution significantly increased energy expenditure (P < 0.0001). Drinking water that had been cooled to 3 C caused a small increase in energy expenditure of 4.5% over 60 min (P < 0.01). CONCLUSIONS: Drinking distilled water at room temperature did not increase energy expenditure. Cooling the water before drinking only stimulated a small thermogenic response, well below the theoretical energy cost of warming the water to body temperature. These results cast doubt on water as a thermogenic agent for the management of obesity.
Authors: Piotr Kocełak; Agnieszka Zak-Gołąb; Anna Rzemieniuk; Joanna Smętek; Ryszard Sordyl; Agata Tyrka; Maciej Sosnowski; Barbara Zahorska-Markiewicz; Jerzy Chudek; Magdalena Olszanecka-Glinianowicz Journal: Arch Med Sci Date: 2012-12-19 Impact factor: 3.318