These sweeteners show up in a wide range of everyday foods and drinks like diet sodas, flavored waters, protein bars, low-calorie yogurts, sugar-free candies, and even some condiments and sauces. Because they’re calorie-free, they’ve long been recommended as a tool for weight management and blood sugar control, particularly for people with or at risk for type 2 diabetes. That claim is now under scrutiny, with new research contradicting that recommendation.