It has often been recommended in popular weight-loss programs that overweight and obese individuals hoping to shed unwanted pounds should drink more water.
As is often the case, the evidence base behind this recommendation was rather scant. Fortunately, a study published in the journal Obesity suggests the recommendation may be quite sound.
In the study, Dennis and colleagues randomized overweight/obese older men and women to either a hypocaloric diet alone or a hypocaloric diet plus increased water consumption for a duration of 12 weeks.
The hypocaloric diet consisted of 1200 calories for the women and 1500 calories for the men. Those in the diet + increased water group were required to consume 500 ml of water (2 cups) 30 minutes prior to each of the 3 large daily meals (breakfast, lunch, dinner).
And what did they find?
While participants in both groups lost a significant amount of weight (5-8kg) in response to the diet, those who also consumed more water before their meals lost an additional 2 kg in comparison to the diet only group.
The greater weight loss in the group consuming pre-meal water could be the result of smaller caloric intake during each meal (~40 calories less per meal), as shown during the baseline laboratory test meals comparing no-water to water meal conditions in all the subjects.
While this is the first randomized trial to investigate the effect of increased water consumption on weight loss, the findings are in agreement with prior epidemiological studies showing that caloric intake in water drinkers is on average 200 calories less than among non water drinkers.
This study provides compelling evidence to encourage all those attempting to lose weight to increase their daily intake of water to help in their efforts. Specifically, one should consume approximately 2 cups of water, about half an hour prior to most meals.
As Travis has previously described, drinking more water will also have the added bonus of forcing you to take bathroom breaks, thereby increasing your level of physical activity.
News source: Public Library of Science. The content is edited for length and style purposes.
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