104-Week Study Finds Non-Nutritive Sweetened Beverages and Water Equally Effective for Weight Management
A new 104-week randomized controlled trial from researchers at the University of Liverpool found that non-nutritive sweetened (NNS) beverages and water were equally effective for long-term weight management when consumed as part of a behavioral weight-management program.
The study, published in the British Journal of Nutrition, followed adults with overweight or obesity for two years and compared the effects of commercially available NNS beverages with water on weight loss, weight maintenance, and metabolic health.
The SWITCH Trial
The study was part of the SWITCH Trial, which examined whether NNS beverages could support weight management over the long term.
Participants first completed a 12-week behavioral weight-loss program, followed by 40 weeks of supported weight maintenance and a final 52-week period without regular weight-management support.
What Was Studied?
The trial included 493 adults with overweight or obesity who were randomly assigned to consume either water or commercially available NNS beverages. 220 completed the final 52-week monitoring phase.
The NNS beverages contained one or more of three commonly used low- and no-calorie sweeteners: aspartame, acesulfame potassium (ace-K) and sucralose.
Participants in the NNS group were asked to consume at least two servings of NNS beverages daily, while the water group was asked to avoid NNS beverages.
Key Findings
After 104 weeks:
- Equivalent weight loss between NNS beverages and water over two-year period.
- Participants consuming NNS beverages lost an average of 10.6 lbs. from baseline.
- Participants consuming water lost an average of 8.2 lbs.
- Decrease in waist and hip circumference and improvement in body composition, and several metabolic biomarkers in both groups.
- Decrease in waist and hip circumference and improvement in body composition, and several metabolic biomarkers in both groups.
- Sugar intake decreased in both groups, with a somewhat greater reduction among participants consuming NNS beverages.
- No clinically meaningful difference in effects such as blood pressure and cholesterol, associated with long-term consumption of either aspartame, acesulfame‑K, or sucralose or water.
What Do the Findings Mean?
The SWITCH Trial provides two years of randomized controlled trial evidence on the use of NNS beverages during weight loss and long-term weight maintenance.
The findings show that participants who consumed NNS beverages achieved and maintained weight loss comparable to those who consumed water. This adds to the evidence from randomized controlled trials examining the role of NNS beverages as one option for reducing sugar and calories while maintaining sweetness.
The study also provides longer-term evidence relevant to ongoing discussions about the role of NNS beverages in weight management.
Conclusion
The 104-week SWITCH Trial found that NNS beverages and water were equivalent for long-term weight management. Participants in both groups maintained significant weight loss over two years, while also experiencing improvements in measures including waist circumference and several metabolic outcomes.
The findings directly address recent World Health Organization (WHO) guidance, which advised against using non-sugar sweeteners for weight control due to uncertainty in observational studies. The SWITCH trial provides long-duration, randomized controlled evidence which can be used to inform global guidelines.
Related Resources
- Read the press release
- Learn more about sweeteners.