The researchers divided the two groups of obese men and women aged 55-75: one group was asked to follow a diet, low fat low in calories, while another group was asked to follow the same diet and drank two cups of water before breakfast, lunch and dinner.
After 12 weeks, people who drink water before eating has lost 15.5 pounds, compared with 11 pounds for those who do not drink the water. The difference of weight loss both groups nearly 30%.
The researchers got the idea for weight loss programs from their previous research. They found that when middle-aged adults and older to drink water before eating, their food fewer calories between 75 and 90 calories.
Although they are not sure about that, but drinking water will compensate by eating more throughout the rest of the day, said senior researcher Brenda Davy, professor in the Department of Nutrition, Food and Sports at Virginia Tech. But after 12 weeks of diet, it did not happen.
"Drinking water is a fairly simple strategy that can help people trying to lose weight," said Davy. "We're not saying, 'Drink more water and body fat will melt away'. But for people who are trying to lose weight and try to follow a low calorie diet, they can try."
The results of this study will be presented at the annual meeting of the American Chemical Society in Boston, next week.
"One of the most annoying problem with dieting is how difficult it is to maintain weight loss long term," said Davy. After 12 weeks, Davy and his colleagues continue to follow the participants.
After one year, preliminary data showed that those who continue to drink water before eating not only maintain weight, but continued to lose weight an average of 1.5 pounds.
"But the group drank water before meals come with a warning: this method only works if you are already middle-aged or older," said Davy.
Previous research has shown that in the group drinking water before eating aged 18-35, did not cause them to consume fewer calories at dinner, said Davy.
In older people, it takes longer to empty the stomach. This allows water to help them feel fuller and less hungry. "While the young people, the water will soon leave the stomach," said Davy.
Barry Popkin, director of the Obesity Nutrition Research Center at the University of North Carolina said the findings 'promising'. His research showed people who drink lots of water is slightly sweet, eat more fruits and vegetables, eat fewer calories overall during the day.
"One culprit in the epidemic of obesity is that Americans consume about 300 calories more a day in sweet drinks than they did 30 years ago," Popkin added. That includes soda, drinks and fruit juices with added sugar, sports drinks and sweet tea.
"If you drink more water just before eating, there is the potential you may reduce your food intake," Popkin said. "We worry about the effort to encourage people to drink water to replace all the calories from the drinks we drink."
"Another challenge to the group meninum water before eating is a strategy of weight loss make people want to do it," said Carla Wolper, assistant professor at the Center for Eating Disorders at Columbia University and a member of the researcher in New York Obesity Research Center at St. Luke's Hospital in New York City.
The same applies to drink more water. Even small changes that seem to require a commitment. "Changing patterns of complex behavior, and it takes time and energy," said Wolper.
"Experts often recommend a diet of non-calorie beverages like soda with lemon, diet soda or tea to help resist the urge to nibble after dinner," said Wolper.
