I think it's konjac. Konjac is a natural diet food with high fiber, low fat and low calorie. It contains about 60% mannan and has strong water absorption. After absorbing water, the volume expands, which can fill the stomach and eliminate hunger. Amorphophallus konjac can delay the digestion and absorption of nutrients, reduce the absorption of monosaccharides and reduce the synthesis of fatty acids in the body. Because it contains extremely low calories, it can control the weight gain, so it can achieve the purpose of losing weight. The higher the purity of konjac, the smaller the particle size and the more obvious the effect.