Nature's Way Glucomannan is a best-selling glucomannan (GLUE-co-man-an) supplement, used to decrease appetite to safely promote weight loss. Glucomannan, also known as konjac root, contains high amounts of soluble fiber, which, when taken with water before meals, expands to occupy space in your digestive system. While delivering all the other benefits of fiber - like regular elimination and support for healthy cholesterol levels - glucomannan supplements are also effective fiber-based appetite suppressants free from stimulant effects or side-effects.