A diet drink is a drink formulated to be low in calories — typically a reduced-calorie version of a popular soft drink, made by replacing sugar with intense sweeteners such as aspartame, sucralose, or stevia. The category was built on the promise of sweetness without energy, aimed at weight-conscious consumers and people managing diabetes. The technology is harder than it looks: sugar provides body and mouthfeel as well as sweetness, so formulators add gums, adjust acidity, and blend sweeteners to mask each other’s aftertastes. The health debate around diet drinks is lively — observational studies link heavy consumption to weight gain and metabolic issues, though the causality is disputed and may run the other way, with people at risk choosing diet drinks. Regulators consider the approved sweeteners safe within acceptable daily intakes, and the category keeps growing.