A major 104-week clinical trial has demonstrated that non-nutritive sweetened soft drinks perform equivalently to water for long-term weight management. Researchers at the University of Liverpool and the University of Leeds followed 493 adults with overweight or obesity, providing strong evidence that swapping sugar for diet beverages does not hinder a structured behavioural weight management programme.
Equivalent Results to Water
The SWITCH trial, published in the British Journal of Nutrition, compared the daily consumption of water against commercially available diet drinks containing aspartame, acesulfame-K, or sucralose. Over two years, participants in both groups experienced sustained weight reduction, with no clinically meaningful difference in weight lost between the two choices. The findings directly contradict concerns that zero-calorie sweeteners disrupt appetite regulation or induce metabolic harm.
Addressing Public Health Guidance
Beyond shedding weight, participants saw improvements in body composition, waist circumference, and metabolic biomarkers regardless of which beverage they consumed. Both groups successfully reduced their overall sugar consumption, with the sweetener cohort seeing slightly greater decreases. According to the published trial results, this data fills a critical gap in international discussions, offering rigorous long-duration evidence to inform future World Health Organization guidelines on non-sugar sweeteners.