The SUBstituting with Preferred OPtions (SUB-POP) trial, is a parallel-arm randomized controlled trial (RCT) to test the effects of substituting SSBs with non-caloric options on body weight and markers of type 2 diabetes and cardiometabolic health. Eligible adult participants will be randomized to 1 of 4 beverage groups and receive at-home monthly deliveries of beverages for 6 months. In-person clinic visits will be conducted at baseline, 6, and 12 months. After the 6 months of assigned beverage substitution and delivery, all participants will be instructed to substitute SSBs with water only for a final 6-month observational period. In-person clinic visits will collect technician-measured anthropometrics, blood pressure, biospecimen samples (blood, urine, stool \[subset\]), and assess physical activity, diet, beverage frequency, and taste preference. The SUB-POP app-based assessments and online diet recall will ascertain daily beverage intake, while diet (via 3 24-hour recalls), physical activity, and overall beverage frequency will be collected every 1-3 months. A subset will receive at-home digital scales to transmit daily body weight for energy balance and caloric compensation modeling. SUB-POP is a novel RCT that will enroll adult regular SSB consumers with overweight or obesity to evaluate the effectiveness of substituting SSBs with non-caloric options in a real-world, un-blinded setting. The trial will leverage social media recruitment methods, achieve ≥30% non-White participants, implement innovative intervention delivery, adherence, and data collection tools, and partition the artificially-sweetened beverage (ASB) substitution intervention to the two most common artificial sweetener types (aspartame, sucralose) to explore potential heterogeneity. Whether ASBs, which are largely free of calories and sugar, provide a healthful interim strategy to transition to water among habitual SSB consumers is unknown. Thus, by addressing this large gap in the understanding of how to address a highly prevalent and concerning dietary exposure, the investigators will inform dietary guidelines and clinical recommendations for the prevention of obesity, type 2 diabetes, and cardiometabolic disease risks. The primary outcomes are change in body weight from baseline to 6 months between the 3 beverage substitution groups (aspartame ASBs, sucralose ASBs, and water) vs. the maintain SSBs control group, adjusting for multiple comparisons. The investigators and staff will be blinded to group assignment at outcome assessments. Intention-to-treat analysis will be used.

After 9/1/2023 the 2 ASB intervention groups (sucralose, aspartame) are combined into a single ASB intervention group; participants randomized on or after 9/1/2023 will be randomized to 1 of 3 beverage groups: maintain SSBs (months 0-6; then switch to water months 6-12); switch to ASBs (months 0-6; then switch to water months 6-12); switch to water (months 0-12). The primary outcomes are change in body weight from baseline to 6 months between the 2 beverage substitution groups (ASBs \[all ASB intervention groups combined\] and water) vs. the maintain SSBs control group, adjusting for multiple comparisons.