Allulose is also known as D-psicose. It is classified as a "rare sugar" because it is naturally present in only a few foods. Wheat, figs and raisins all contain it. Like glucose and fructose, allulose is a monosaccharide, or single sugar. In contrast, table sugar, also known as sucrose, is a disaccharide made of glucose and fructose joined together.
According to allulose manufacturers, allulose has the same chemical formula as fructose, but is arranged differently. This difference in structure prevents your body from processing allulose the way it processes fructose. In most cases, foods with allulose enjoy a higher popularity among people because they are considered safer and healthier.