MONDAY, Aug. 23 (HealthDay News) -- Close the diet books and skip the pills. The latest weight-loss trick may be as simple as gulping a couple of glasses of water before you eat.
A new study found that middle-aged and older adults who drank two cups of water before each meal consumed fewer calories and lost more weight than those who skipped drinking water.
Researchers divided two groups of overweight and obese men and women aged 55 to 75 into two groups: one group was told to follow a low-fat, low-calorie diet; the other group was told to follow the same diet and to drink two cups of water before breakfast, lunch and dinner.
After 12 weeks, those who drank water before meals had lost 15.5 pounds, compared to 11 pounds for the non-water drinkers, a nearly 30 percent difference.
The researchers got the idea for the weight-loss program from their prior research, which found that when middle-aged and older adults drank water before meals, they ate between 75 and 90 fewer calories at the meal.
What they weren't sure about, however, was if water drinkers would compensate by eating more throughout the rest of the day, said senior study author Brenda Davy, an associate professor in the department of human nutrition, foods and exercise at Virginia Tech. But after 12 weeks of dieting, that didn't happen.
"Drinking more water is a pretty simple strategy that may be helpful to people trying to lose weight," Davy said. "We're not saying, 'Drink more water and the body fat will melt away'. 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."
The research was to be presented Monday at the annual meeting of the American Chemical Society in Boston.
One of the most vexing issues with dieting is how difficult it is to keep the weight off long-term, Davy said. After the 12 weeks were up, Davy and her colleagues have continued to follow the participants.
After one year, preliminary data shows that those who continued to drink water before meals not only kept those pounds off, but have even continued to lose a bit more -- about 1.5 pounds on average.
Yet pre-meal water chugging comes with one caveat: it may only work if you're middle-aged or older, Davy said.
Prior research has shown that in those aged 18 to 35, drinking water before the meal did not cause them to eat fewer calories at the meal, Davy said.
In older people, it takes longer for the stomach to empty, which may be why the water helps them feel fuller and less hungry, while in younger people, water begins leaving the stomach almost immediately, Davy said.
Barry Popkin, director of the University of North Carolina Nutrition Obesity Research Center, called the findings "promising." His research has shown people who drinks lots of water drink fewer sugary beverages, eat more fruits and vegetables and overall consume fewer calories throughout the day.
One culprit in the obesity epidemic is that Americans consume some 300 calories more a day in sugary beverages than they did 30 years ago, Popkin added. That includes soda, punch and fruit juices with added sugar, sports drinks and sweetened tea.
"If you drink some more water right before a meal and fill up a little bit right before, there is the potential you may reduce your food intake," Popkin said. "But what we're concerned with is encouraging people to drink water to replace all the caloric beverages we're drinking."
Another challenge to the water-before-meals weight-loss strategy is getting people to do it, said Carla Wolper, an assistant professor in the Eating Disorders Center at Columbia University and a research faculty member at the New York Obesity Research Center at St. Luke's Hospital in New York City.
"The question is, do people continue to drink the water in a non-study situation?" Wolper said. "We know there are a lot of simple things people could do to lose weight. Clinical trials have shown if people write down what they eat, they lost twice as much weight. Yet it's very hard to get people to write down what they eat. Or, if people would reduce portions just a little bit, they would lose weight. But people don't do it."
The same goes for drinking more water. Even seemingly small changes require commitment. "Changing a pattern of behavior is complicated, and requires time and energy," Wolper said.
Still, it could be worth a try, she added. "Unless people overload on water, it's harmless, inexpensive. And if over the course of the entire day, it reduces the amount of food people take in, then of course it's a good idea," Wolper said.
Dieticians often will suggest a non-caloric drink such as club soda with lemon, diet soda or tea to help resist the urge to snack after dinner, Wolper said.
The Harvard School of Public Health has more on eating a healthy diet.