Non-nutritive sweeteners and body weight management: another brick in the wall of evidence

In this issue, Harrold et al. [1] report outcomes at 52-weeks of their randomised controlled trial (RCT), called SWITCH, which compared consumption of beverages sweetened with non-nutritive sweeteners (NNS), with consumption of water. The authors deserve to be congratulated on performing a well-powered, long-term RCT with significant relevance to public health – in part they did this under restrictions necessitated by the COVID-19 pandemic. Participants in the trial were women and men with overweight or obesity, enroled in a weight management programme, comprising 12 weeks active weight loss and 40 weeks weight maintenance support (with a planned follow-up after a further 52 weeks of unassisted weight maintenance, which is ongoing). Outcomes at 12 weeks were published earlier this year [2]. There was weight loss of 6.3% at 12 weeks, which was maintained at 52 weeks (7.5%) (complete cases datasets). At 52 weeks, the weight loss was statistically significantly greater for the participants randomised to NNS beverages versus those randomised to water (7.5 kg versus 6.1 kg). So, as well as achieving and maintaining successful weight loss, this new RCT provides evidence of a small advantage for weight management of consuming NNS beverages over water.