Diet drinks as effective as water for weight loss, 104-week study finds

A 104-week clinical trial of 493 adults found that diet beverages containing non-nutritive sweeteners performed similarly to water in supporting long-term weight loss and maintenance.

Researchers at the University of Liverpool and the University of Leeds conducted what they described as the most comprehensive randomized controlled trial to date on non-nutritive sweetened (NNS) beverages. The SWITCH trial, published in the British Journal of Nutrition, tracked adults with overweight or obesity participating in a behavioral weight management program. Participants were randomly assigned to consume either water or commercially available diet drinks daily.

According to reports from ScienceDaily and ScienceDa, the study provided clinical evidence on beverages containing aspartame, acesulfame potassium, and sucralose. The findings indicated these drinks were comparable to water for both weight loss and long-term maintenance. Researchers noted that the amounts of sweeteners consumed remained within safety thresholds established by the European Food Safety Authority.

The research team, led by Professor Jo Harrold and Professor Jason Halford, stated that the results did not support concerns that diet beverages interfere with appetite regulation or cause long-term metabolic harm. Professor Harrold noted that these findings from a rigorous trial show that claims of sweeteners disrupting appetite or causing weight gain are unsupported.

The study was funded by the American Beverage Association, though researchers stated the team operated independently and retained full control over the analysis and reporting of results. The researchers expressed hope that this long-term evidence would help inform future public health policy and global recommendations.

Background

The trial results are relevant to recent World Health Organization guidance advising against the use of non-sugar sweeteners for weight control due to uncertainty in observational research.