Background
Intake of sugar-sweetened beverages has been associated with weight gain. It is uncertain if replacing an existing use of sugar-sweetened beverages with non-caloric beverages results in long-term reduction in body weight.

Objective
The objective of this study is to explore if a long-term reduction in body weight can be achieved by replacing an existing intake of sugar-sweetened beverages with non-caloric beverages.

Methods
Systematic review and meta-analysis of randomized clinical trials in accordance with PRISMA guidelines. PubMed and EMBASE were searched for literature. Studies with a “substitution” design were included, that is, studies where subjects substituted an existing intake of sugar-sweetened beverages with either artificially sweetened beverages or unsweetened beverages/water. Studies with 6 months or longer follow-up of weight change were included.

Results
Six trials with a total of 1729 participants were included in the meta-analysis. Replacing an existing intake of sugar-sweetened beverages with a non-caloric beverage resulted in a long-term BMI reduction of 0.31 kg/m2 compared with the sugar-sweetened beverage-group (95% CI; 0.17–0.44). One study with 1 year's intervention and 2 years follow-up showed a regression towards baseline BMI after the intervention had ended.

Conclusion
Replacing an existing use of sugar-sweetened beverages with artificially sweetened beverages or unsweetened beverages resulted in a long-term 0.31 kg/m2 reduction in BMI equivalent to 0.5–1 kg in children and adults, respectively, as long as the interventions lasted.