Rationale, Design and Baseline Characteristics for the Strategies to Oppose SUGARS with Non-nutritive Sweeteners or Water (STOP Sugars NOW) Trial

Health authorities recommend reducing added or free sugars to ≤5–10% energy. Much attention has focussed of the reduction of SSBs with the recommendation that SSBs be replaced with unsweetened healthy alternatives such as water but not non-nutritive sweetened beverages (NSBs). There are concerns that non-nutritive sweeteners do not have the intended benefits and may induce glucose intolerance through changes in the gut microbiome. Whether NSBs have benefits similar to water in their intended substitution for SSBs is unclear. To address this question, we have undertaken the STOP Sugars NOW trial (NCT03543644), a pragmatic “head-to-head” crossover randomized controlled trial of the effect of NSBs (the intended substitution) versus water (the standard of care) as a replacement strategy for SSBs on glucose tolerance and gut microbiome diversity. We recruited overweight or obese participants with a high waist circumference who regularly consume ≥1 SSBs/day. Each participant underwent a ≥2-week run-in period followed by three 4- week treatment phases in random order (usual SSBs, equivalent NSBs, or water) with each phase separated by a ≥4-week washout. The two primary outcomes are change in glucose tolerance and gut microbiome beta- diversity. Adherence to the interventions will be assessed by objective biomarkers of added sugars (13C/12C isotopic ratio in serum fatty acids and urinary fructose and sucrose) and non-nutritive sweeteners (urinary sucralose and acesulfame-potassium). The trial started on June 1st, 2018 with the first participant undergoing randomization on August 1st, 2019 and the last participant finishing on October 15th, 2020. We screened 1,086 individuals, out of which 80 were randomized. Baseline characteristics showed a mean age of 41.8 ± 13.0 y, BMI of 33.7 ± 6.8 kg/m2, waist circumference of 108.7 ± 13.5 cm, and mean SSBs intake of 2 SSBs/day. The results of this trial will directly inform public health guidance on the use of NSBs in sugars reduction strategies. CIHR.