If you're cutting calories, drinking two cups of water before every meal can help you lose more weight than dieting alone. That’s the finding of a  study presented at the 240th National Meeting of the American Chemical Society in Boston.

“In spite of popular beliefs that this is a weight loss strategy, it had never actually been studied in a clinical trial,” says lead author Brenda Davy, PhD, associate professor in the Department of Human Nutrition, Foods and Exercise at Virginia Tech
 in Blacksburg.

This study followed 48 adults between the ages of 55 and 75 who were on a low-calorie diet for three months. Half the group was told to drink two eight-ounce glasses of water three times a day before every meal. The other half was given no instructions about what to drink or when. After 12 weeks, those who drank the prescribed amount of water before meals lost about 15.5 pounds. The group who didn’t lost about 11 pounds.

“The idea was that this may help to manage hunger and fullness and help them adhere to the low-calorie diet,” says Davy.

Davy believes water works by filling up the stomach with something that has no calories. But she warns that dieters shouldn't attempt this strategy with juice, soda or other high-calorie beverages.

“One important point is that, as Americans, we consume about 400 to 450 calories from beverages over the course of a day. So for people who do consume a lot of calorie-containing beverages, simply replacing the calorie-containing beverages with water could be a way to reduce our calorie intake,” Davy says.