Single-trial comparisons were identified in participants living with obesity (comparing NNS beverages sweetened with sucralose vs. water control), examining postprandial insulin response in participants with type 1 diabetes (comparing NNS beverages sweetened with sucralose + ace-K vs. water control), examining postprandial insulin, GLP-1, GIP, and glucagon responses in type 2 diabetes (comparing NNS beverages sweetened with sucralose + ace-K vs. water control), and examining postprandial GIP and glucagon responses. Here, GIP is linked to obesity due to melanocortin 4 receptor deficiency.