Sweetness is one of the five basic tastes and is almost universally regarded as a pleasurable experience. Foods rich in simple carbohydrates such as sugar are those most commonly associated with sweetness, although there are other natural and artificial compounds that are sweet at much lower concentrations, allowing their use as non-caloric sugar substitutes.
Examples of foods that may be used as non-sugar sweet substitutes include saccharin, aspartame, xylitol and acesulfame K. Other compounds may alter perception of sweetness itself. The chemosensory basis for detecting sweetness, which varies among both individuals and species, has only been teased apart in recent years. A recent theoretical model of sweetness is the multipoint attachment theory, which involves multiple binding sites between a sweetness receptor and a sweet substance.