Middle-aged and older adults ate fewer calories and shed more pounds when they drank two cups of water before a meal compared with those who didn’t, according to research presented at the American Chemical Society meeting and reported by HealthDay News.

For the study, researchers at Virginia Tech divided overweight and obese participants, ages 55 and 75, into two groups. One followed a low-fat, low-calorie diet while the other followed the same diet but also drank two cups of water before each of their three daily meals.

After a three-month follow-up, those in the group who drank water lost an average of five more pounds than those who didn’t drink water. And they also realized an added bonus. Downing a couple glasses of water before a meal helped them keep weight off. One year later, researchers found that dieters who continued to drink their pre-meal water didn’t regain any weight, plus they lost, on average, an extra 1.5 pounds.

“Drinking more water is a pretty simple strategy that may be helpful to people trying to lose weight,” said lead author Brenda Davy, PhD, RD, an associate professor in the department of human nutrition, foods and exercise at Virginia Tech.

How exactly did drinking water help? Apparently, it takes longer for water in the stomach to empty in older people, making them feel fuller and less hungry for longer. But only older adults experienced H2O benefits.

Previous studies showed that water left the stomachs of people ages 18 to 35 almost immediately, providing no diet benefits.

Still, this research could help fight the obesity epidemic in America. How? Because it showed that if people drank water directly before and after meals, they ate much less food. But the hard part is getting people to drink water instead of high-calorie beverages, researchers explained.

“We’re not saying ‘Drink more water and the body fat will melt away,’” Davy said. “But for people who are trying to lose weight and trying to follow a low-cal diet, it’s something they can do as part of that.”

Click here to read why drinking fewer sugary beverages is better for your health.