Effect of non-nutritive sweetened beverages versus water on body weight: long-term results of a randomised controlled trial.

The aim of this study was to provide robust evidence on the long-term use of non-nutritive sweetened (NNS) beverages on weight management, by comparing NNS beverages and water during 1 year of assisted weight management followed by a voluntary, unassisted 1-year extension. In this parallel-group, open-label, controlled equivalence trial, 493 adults with body mass index 27-35 kg/m2 who regularly consumed cold beverages were randomised 1:1 to water (n 246) or NNS beverages (n 247). Participants joined a group behavioural weight-management programme comprising assisted meetings weekly (12-week weight-loss phase) then monthly (40-week weight-maintenance phase), followed by unassisted monitoring for 52 weeks with a final meeting at week 104. The final 52 week unassisted phase was completed by 220 participants (water: n 117; NNS beverages: n 103), 27·7% of whom were NNS beverage-naïve (naïve was defined as NNS beverages comprising ≤ 25% of beverages in the 5 years before screening). In the unassisted monitoring phase, the primary endpoint was weight change from baseline at week 104 (equivalence: two-sided P > 0·05). Participants consuming water maintained a weight loss of 3·7 kg over 104 weeks, compared with 4·8 kg with NNS beverages; the between-group difference was not significant. After the final 52-week unassisted phase of the 104-week behavioural weight-management programme, water and NNS beverages showed equivalence regarding weight change from baseline. Our findings suggest people can lose weight, and maintain it for two years, when drinking either NNS beverages or water and taking part in weight-management programmes.