Dieters who drink
more water have greater weight loss, according to a new review of several prior
studies. In one study that asked dieters to drink water before a meal, for
instance, "the water enhanced the weight loss," said Brenda Davy, a
professor at Virginia Tech who led some of the work included in the review.
Researchers said there is not yet enough evidence, however, to say for sure
that drinking more water will help people shed the pounds.
Rebecca Muckelbauer, a researcher at the Berlin School of
Public Health, Charit? University Medical Center Berlin in Germany, led the new
review of the water studies. She said that, as a nutrition researcher, people
had often asked her about whether they should drink water to lose weight, and
she didn't know the answer. She and her colleagues decided to examine all of
the studies on weight and water consumption. Eleven studies fit their criteria.
Three of them showed that increased water intake among
dieters was tied to greater weight loss. a study by Davy's group found that
middle aged and older adults who drank two cups before a meal lost about four
pounds more than a group that didn't drink the extra water.
Yet another study found that women who increased their water
consumption while they dieted lost more weight than those who kept it below one
liter a day. It’s not clear how water might help people shed pounds.One
possibility, said Davy, is that water could squelch feelings of
hunger."This may have helped them reduce their calorie intake," she told
Reuters Health. Muckelbauer agreed that increased fullness is the most likely
explanation, but another possibility is something called "water-induced thermogenesis."The
idea is that drinking water itself increases energy expenditure of your body.
It has an energy consuming effect, this is not very well studied,"
Muckelbauer told Reuters Health.
The Institute of Medicine recommends that adults consume
between 91 ounces of water for women and 125 ounces for men (2.7 - 3.7 liters)
each day, but this total can come through food, plain water or other beverages.
While the experimental studies suggest that drinking water may aid in weight
loss, the surveys Muckelbauer examined don't always show that people who drink
more water are slimmer.
In fact, some found that obese or overweight adults drank
more water than people of normal size, while others did not find such a link,
Muckelbauer's team reports in the American Journal of Clinical
Nutrition."We don't have conclusive evidence that increasing water intake
reduces weight, but there are certainly other benefits to increasing our
intake," said Davy.
She said people in the US typically drink about 400 to 500
calories a day from other beverages, and replacing them with water is not a bad
One study found that women who drink water, rather than
sweet drinks, had a slightly lower chance of developing diabetes (see Reuters
Health story of May 31, 2012 here: And women who don't drink plenty of water
have greater odds of getting kidney stones (see Reuters Health report of March
29, 2012 here: "There's not a lot of risk for recommending (increased
water intake) for individuals," Davy said.
Muckelbauer said it will be helpful to have larger
experiments looking at the potential weight loss benefits of adding more water
to the diet.