Study Compares Weight Loss Effects of Diet Soda and Water

<p>A study conducted by the University of Liverpool found that diet drinks containing sugar substitutes were as effective as water for supporting weight loss in overweight or obese adults. The two-year randomized trial included 493 participants aged 18 to 65, all with a body mass index (BMI) between 27 and 35.</p><p>Participants were divided into two groups: one group consumed 22.3 ounces of water daily, while the other group consumed the same amount of soda with non-nutritive sweeteners (approximately two cans) over a 104-week period. The diet soda group had options including various diet sodas, low-calorie fruit drinks, and flavored waters, with primary sweeteners being aspartame, acesulfame potassium, and sucralose.</p><p>After two years, the diet beverage group lost an average of 10.6 pounds, while the water group lost about 8.2 pounds. Both groups maintained a significant amount of weight loss over the two years, even after the cessation of regular weight-management support. Participants in both groups also experienced reductions in waist and hip measurements and body fat, with no significant differences between the two groups.</p><p>Cholesterol levels remained within a healthy range for both groups. Alix Turoff, a registered dietitian in New York City, noted that the study does not imply that diet beverages directly caused weight loss, as all participants were involved in a structured weight-management program that included nutrition counseling, behavioral support, and physical activity recommendations.</p><p>Turoff emphasized that the inclusion of diet beverages is more about substitution rather than any unique metabolic effect. The study specifically compared diet beverages to water rather than sugar-sweetened drinks, assessing whether sugar substitutes hinder weight loss efforts.</p><p>She also pointed out that the findings do not suggest that water and diet soda are nutritionally equivalent. The study did not find significant differences in hunger or sugar intake between the groups at the end of the trial, addressing concerns that artificial sweeteners might increase appetite or lead to compensatory eating.</p><p>While Turoff recommends water as the primary hydration choice, she stated that individuals need not fear diet drinks as they do not automatically prevent fat loss or cause weight gain. The study had limitations, including being conducted at a single location in England and lacking data on race and ethnicity, which affects the generalizability of the results.</p><p>Only 220 of the original 493 participants completed the 104-week assessment, and the second-year extension was voluntary, which may have influenced the motivation of those who continued. The trial was funded by the American Beverage Association, but the authors clarified that the association did not participate in the study's design, data analysis, or interpretation of results.</p>