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Participants in a study reported feeling a little more full and a little less hungry after drinking two glasses of water.SHANNON STAPLETON

It's long been suggested that drinking water can help with weight loss, but now a small scientific study lends some credence to the claim.

Researchers presented a paper Monday at the American Chemical Society conference in Boston on a randomized controlled trial involving obese people aged 55 to 75 who were put on a diet.

One group drank two cups of water before their meals, and the other group did not.

Over a 12-week period, the water drinkers lost about 15.5 pounds, while the other group lost about 11 pounds.

The study's senior author, Brenda Davy of Virginia Tech, says the participants were followed up for another year as they continued their weight-loss efforts to see if they could keep the pounds off.

She says the water-drinking group appeared to do a little bit better.

"A very simple message is that in the U.S., we consume about 450 calories from beverages each day," Dr. Davy said in an interview.

"And so this might be a very simple strategy to cut back on calories by replacing some of the sugar-sweetened beverages we often consume with water. And as part of a weight-loss effort, drinking more water may help individuals be even more successful."

Dr. Davy said a paper on the original 12-week study was published in February in the journal Obesity, and the new data on the one-year follow-up was reported at the Boston conference.

The 48 adults in the study were all in the obese range, with a body mass index, or BMI, in the range of 33, she said.

But Dr. Davy noted that consumption of too much water can cause problems.

The Institute of Medicine in the United States recommends that adults drink about nine to 13 cups a day of total fluids just to prevent dehydration, she said. The institute says that in very rare cases, reports of acute water intoxication have surfaced, according to Dr. Davy.

Low sodium can also result from drinking abnormally large amounts of fluid in a short period of time. But Dr. Davy noted that that would far surpass the consumption levels in their study.

Dr. Davy said participants did not report any problems handling two cups of water prior to their meals.

"In fact, during the weight-loss study, many of the participants remarked to us that they felt like their mind was clear, they were thinking a lot better, those types of sort of subjective reports of benefits with the water consumption," she said.

"We did study hunger and fullness, and we did find that after the water consumption, our participants reported feeling a little more full and a little less hungry, which may have facilitated them eating less."

The Canadian Press