If you drink lots of water, you lose weight. This is a widespread belief. But is there any truth in it? Now, a research team at Charité Universitätsmedizin Berlin has examined this notion in a comprehensive meta-study. The researchers evaluated studies published in professional literature that concerned the relationship between water intake and weight reduction. Their analysis showed that although drinking water cannot induce weight loss by itself, it might have a supportive effect for weight loss in combination with a diet. The results of their study have been published in the current issue of the American Journal of Clinical Nutrition*.
Numerous dietary regimens in non-scientific publications and on Internet sites promise that drinking lots of water helps with weight loss. The presumable reason for this belief is the rapid sense of satiety that occurs if one drinks water before a meal. Another hypothesis claims that drinking water boosts energy consumption thereby increasing basal metabolism. “Although dietary programs often recommend drinking lots of water, until now there has been no scientifically based justification for such recommendations. Given the widespread prevalence of this subject, it is surprising that relatively few studies to date have examined the relationship between body weight and water drinking,” states Dr. Rebecca Muckelbauer, a nutritional scientist at Charité’s Berlin School of Public Health (BSPH) and lead author of the study.
The researchers searched through four international electronic databases for scientific articles written in English, Spanish, French and German. However, of the nearly 5,000 references, only a few fulfilled the inclusion criteria. The researchers could not include most of the studies in their analysis due to poor quality or unsuitable content. Ultimately, there were a total of 13 studies that qualified for detailed analysis. Of this group, two interventional studies and an additional longitudinal study showed that increased water consumption in older cohorts had a positive effect on the success of a diet. Those participants who drank about one liter of additional water a day while on the diet lost about one to two kilograms more than those individuals who only followed the dietary program. For healthy adults who were not on a diet, there was no correlation shown with body weight. Six additional cross-sectional studies with participants from different weight classes led to contradictory results.
In the final analysis we can say that drinking water will cause no harm so long as one excludes individuals suffering from cardiac insufficiency or problems with fluid elimination. Also, anyone who drinks water instead of fruit juices or soft drinks will save many calories. Whether increased water consumption can make you thinner above and beyond this is a question that remains to be scientifically proven.
* Muckelbauer, Rebecca; Sarganas, Giselle; Grüneis, Anke; Müller-Nordhorn, Jacqueline. 2013. Association between water consumption and body weight outcomes: a systematic review. In: The American Journal of Clinical Nutrition;98(2):282-99. doi: 10.3945/ajcn.112.055061.
Dr. Rebecca Muckelbauer
Berlin School of Public Health
t: +49 30 450 570 828