This all-natural substance (sold as a dietary supplement), which looks and tastes like regular table sugar, has 40% fewer calories and 75% fewer carbohydrates. Unlike regular sugar, this substance produces only a minimal insulin response. This substance is found in many foods, including berries, plums, cauliflower, lettuce and mushrooms, as well as corncobs and some hardwoods. Numerous studies have found that this substance provides several health benefits, including preventing tooth decay and cavities, reducing dental plaque formation and gingivitis, and promoting the rebuilding of tooth enamel. What is this substance (dietary supplement)?