A sugar substitute is a food additive that provides a sweetness like that of sugar while containing significantly less food energy than sugar-based sweeteners, making it a zero-calorie (non-nutritive) or low-calorie sweetener. Artificial sweeteners may be derived through manufacturing of plant extracts or processed by chemical synthesis. Sugar substitute products are commercially available in various forms, such as small pills, powders and packets.

Common sugar substitutes include aspartame, monk fruit extract, saccharin, sucralose, stevia, acesulfame potassium (ace-K) and cyclamate. These sweeteners are a fundamental ingredient in diet drinks to sweeten them without adding calories. Additionally, sugar alcohols such as erythritol, xylitol and sorbitol are derived from sugars.

No links have been found between approved artificial sweeteners and cancer in humans. Reviews and dietetic professionals have concluded that moderate use of non-nutritive sweeteners as a safe replacement for sugars can help limit energy intake and assist with managing blood glucose and weight.