If you're trying to lose pounds to get to a healthy weight, a new study shows those liquid calories matter, too.
The study, conducted by researchers from the University of North Carolina at Chapel Hill, showed that overweight and obese people who swapped out their caloric drinks for calorie-free options -- including, yes, water! -- were able to lose four to five pounds over a six-month period. The research will be published in the American Journal of Clinical Nutrition.
"If this were done on a large scale, it could significantly reduce the increasing public health problem of obesity," study researcher Deborah Tate, Ph.D., an associate professor of nutrition and health behavior at UNC Chapel Hill, said in a statement.
Tate and her colleagues looked at the amount of weight lost over half a year among 318 overweight and obese people. The study participants were split up into three groups: one group that switched from caloric drinks to simply water, one group that switched from caloric drinks to diet soda, and one group that did not have to change their drink habits, but who received general information what healthy choices to make for weight loss.
All three of the groups experienced some weight loss and smaller waist sizes during the study period, but researchers found that the people who drank the water and diet soda were the most likely to experience weight loss of 5 percent or more of their body weight.
Even more, researchers found that the water-guzzlers were the most hydrated out of the three groups, and had lower levels of fasting glucose than the group who only received the general information.
"Substituting specific foods or beverages that provide a substantial portion of daily calories may be a useful strategy for modest weight loss or weight gain prevention," Tate said in the statement. "Beverages may be ideal targets, but keep in mind, the strategy will only work if the person doesn't make up for the lost calories some other way."
However, past research has shown that diet soda is actually linked with weight gain, with a diet soda a day linked with a 41 percent increased risk of overweight, WebMD reported. (Other studies have also linked the beverage with a higher risk of stroke and heart attack.)
The author of that study, Sharon P. Fowler of the University of Texas Health Science Center, San Antonio, pointed out that the study doesn't mean obesity is caused by diet soda; rather, diet soda is an indicator of behavior that may spur obesity.
"One possible part of the explanation is that people who see they are beginning to gain weight may be more likely to switch from regular to diet soda," Fowler told WebMD. "But despite their switching, their weight may continue to grow for other reasons. So diet soft-drink use is a marker for overweight and obesity."
Last year, Harvard University researchers found that people who swapped out sugar-sweetened drinks for water led to weight loss and a lower risk of Type 2 diabetes. That research was presented at the Sustaining the Blue Planet: Global Water Education Conference.