Are Diet Sweeteners Better for You Than Sugar?
If your actual choice is a regular soda versus a diet one, the diet version is usually the better choice for weight and blood sugar exposure: randomized trials show a small weight benefit and much lower immediate blood sugar and insulin exposure than sugar. That is a substitution argument, not a health claim. Non-sugar sweeteners are not proven to be better than water or unsweetened drinks as a long-term health strategy, and the people who use them most heavily carry higher long-term rates of diabetes and heart disease, though those studies cannot prove the sweeteners caused those outcomes.