When it comes to weight loss, what you drink may be more important than what you eat, according to researchers at the Johns Hopkins Bloomberg School of Public Health. Researchers examined the relationship between beverage consumption among adults and weight change and found that weight loss was positively associated with a reduction in liquid calorie consumption and liquid calorie intake had a stronger impact on weight than solid calorie intake. The results are published in the April 1, 2009, issue of the American Journal of Clinical Nutrition.
“Both liquid and solid calories were associated with weight change, however, only a reduction in liquid calorie intake was shown to significantly affect weight loss during the 6-month follow up,” said Benjamin Caballero MD, PhD, senior author of the study and a professor with the Bloomberg School’s Department of International Health. “A reduction in liquid calorie intake was associated with a weight loss of 0.25 kg at 6 months and 0.24 kg at 18 months. Among sugar-sweetened beverages, a reduction of 1 serving was associated with a weight loss of 0.5 kg at 6 months and 0.7 kg at 18 months. Of the seven types of beverages examined, sugar-sweetened beverages were the only beverages significantly associated with weight change.”
Researchers conducted a prospective study of 810 adults aged 25-79 years old participating in the PREMIER trial, an 18-month randomized, controlled, behavioral intervention. Caballero along with colleagues from the Johns Hopkins School of Medicine; the National Heart, Lung, and Blood institute; Duke University; the Pennington Biomedical Research Center; the Kaiser Permanente Center for Health Research; the University of Alabama; and Pennsylvania State University measured participant’s weight and height using a calibrated scale and a wall-mounted stadiometer at both 6 and 18 months. Dietary intake was measured by conducting unannounced 24-hour dietary recall interviews by telephone. Researchers divided beverages into several 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. They found that at 37 percent sugar-sweetened beverages were the leading source of liquid calories.
Consumption of liquid calories from beverages has increased in parallel with the obesity epidemic. Earlier studies by Bloomberg School researchers project that 75 percent of U.S. adults could be overweight or obese by 2015 and have linked the consumption of sugar-sweetened beverages to the obesity epidemic, which affects two-thirds of adults and increases the risk for adverse health conditions such as type 2 diabetes. Researchers recommend limited liquid calorie intake among adults and to reduce sugar-sweetened beverage consumption as a means to accomplish weight loss or avoid excess weight gain.
“Among beverages, sugar-sweetened beverages was the only beverage type significantly associated with weight change at both the 6- and 18-month follow up periods,” said Liwei Chen, MD, PhD, MHS, lead author of the study and a Bloomberg School graduate. “Changes in the consumption of diet drinks and alcoholic beverages were inversely associated with weight loss, but were not statistically significant. Our study supports policy recommendations and public health efforts to reduce intakes of liquid calories, particularly from sugar-sweetened beverages, in the general population.”