The study, published in the journal Obesity, looked at 303 people over a 12-week period.
Supported by the American Beverage Association, an industry trade association, the study placed participants in two groups. One group was permitted to drink diet beverages, such as diet sodas, teas, and flavored waters. Participants assigned to the control group consumed water only. All of the study subjects followed an identical diet and exercise program.
Diet Soda Drinkers Lost 13 Pounds
Conducted by researchers at the University of Colorado Anschutz Health and Wellness Center in Aurora, Colo., and Temple University’s Center for Obesity Research and Education in Philadelphia, the study found that people who consumed diet beverages lost an average of 13 pounds, which was 44 percent more than the control group, who lost an average of nine pounds.
More than half the participants in the diet beverage group, or 64 percent, lost at least five percent of their body weight, compared with only 43 percent of the control group. Losing just five percent of body weight has been shown to significantly improve health, including lowering the risk of heart disease, high blood pressure, and type 2 diabetes, according to the researchers.
Study co-author Sharon J. Herring, M.D., MPH, assistant professor of Medicine, Public Health, and Ob/Gyn at Temple University, told Healthline, "Our findings suggest that drinking diet beverages will not impede weight loss efforts of dieters who are participating in a behavioral weight loss program or working with their physician to lose weight.”
Moderation Is Key
Commenting on the study findings, Alissa Rumsey, RD, CDN, a registered dietitian and spokesperson for the New York State Dietetic Association, told Healthline, “While artificial sweeteners and sugar substitutes may help with weight management, they aren't a cure-all, and should be used only in moderation. It’s important to make sure you don’t compensate by eating high-calorie foods, such as drinking a diet beverage while eating a big slice of cake.”
Rumsey went on to say that if you replace a high-calorie beverage with a low-calorie beverage, but then eat a high-calorie meal, the potential weight loss benefits will not be fully realized.
“There is some research to suggest people may consume more calories after knowingly having artificially flavored foods, so it is important to watch your overall intake during the day. Foods that have no added sugars should make up the bulk of your diet, including vegetables, fruits, high-fiber whole grains, legumes, and low-fat dairy,” said Rumsey.
Co-author of the study James O. Hill, Ph.D., executive director of the University of Colorado Anschutz Health and Wellness Center, said in a press release, “This study clearly demonstrates diet beverages can, in fact, help people lose weight, directly countering myths in recent years that suggest the opposite effect—weight gain. In fact, those who drank diet beverages lost more weight and reported feeling significantly less hungry than those who drank water alone. This reinforces if you’re trying to shed pounds, you can enjoy diet beverages.”
Co-author John C. Peters, chief strategy officer of the CU Anschutz Health and Wellness Center, said in the press statement, “There’s so much misinformation about diet beverages that isn’t based on studies designed to test cause and effect, especially on the Internet. This research allows dieters to feel confident that low- and no-calorie sweetened beverages can play an important and helpful role as part of an effective and comprehensive weight loss strategy.”
Improvements in Bad Cholesterol
The diet soda drinkers also showed significantly greater improvements in serum levels of total cholesterol and low-density lipoprotein (LDL), also known as “bad” cholesterol, said the researchers. In addition, the diet soda subjects had a significant reduction in serum triglycerides. Both study groups saw reductions in waist circumference and blood pressure.