When it comes to losing weight, what you drink may be more important than what you eat, according to new research, which shows that cutting back on sugar-laden drinks is associated with weight loss and seems to have a bigger impact on weight than cutting back on solid foods.

"Consumption of liquid calories from beverages has increased in parallel with the obesity epidemic in the US population," Dr. Benjamin Caballero of Johns Hopkins Bloomberg School of Public Health and colleagues point out in the American Journal of Clinical Nutrition.

"Our study supports policy recommendations and public health efforts to reduce intakes of liquid calories, particularly from sugar-sweetened beverages, in the general population," they conclude.

The researchers examined how changes in beverage consumption over 18 months affected the weight of 810 adults who participated in a behavior intervention study.

They divided beverages into seven categories based on calorie content and nutritional composition: sugar-sweetened beverages (regular soft drinks, fruit drinks, fruit punch, or high-calorie beverages sweetened with sugar); diet drinks (diet soda and other "diet" drinks sweetened with artificial sweeteners); milk (whole milk, 2 percent reduced-fat milk, 1 percent low-fat milk, and skim milk); 100 percent juice (100 percent fruit and vegetable juice); coffee and tea with sugar; coffee and tea without sugar; and alcoholic beverages.

Sugar-sweetened beverages were the leading source of liquid calories among study subjects. Overall, the researchers found that cutting back on liquid calories was associated with a weight loss of 0.6 pounds (0.25 kg) at 6 months and 0.5 pounds (0.24 kg) at 18 months.

Of the seven types of beverages examined, sugar-sweetened beverages were the only type significantly associated with weight loss. Among sugar-sweetened beverages, cutting out just 1 serving daily was associated with a weight loss of 1.1 pounds (0.49 kg) at 6 months and 1.4 pounds (0.65 kg) at 18 months.

"The weight-loss effect of a reduction in liquid calorie intake was stronger than that of a reduction in solid food intake," Caballero and colleagues report.

The results "support recommendations to limit liquid calorie intake among adults and to reduce sugar-sweetened beverage consumption as a means to accomplish weight loss or avoid excess weight gain," they conclude.

SOURCE: American Journal of Clinical Nutrition, April 2009.