Dietary fiber refers to polysaccharides and lignans that cannot be decomposed by digestive enzymes. It can absorb water from the digestive system; Increasing the amount of food in the stomach can increase satiety; It can also promote gastrointestinal peristalsis and relieve constipation; At the same time, dietary fiber can also absorb harmful substances in the intestine for excretion; Improve intestinal flora and provide energy and nutrition for the proliferation of probiotics. Dietary fiber is a variety of non-starch polysaccharide plant substances, mainly from the cell walls of animals and plants, including cellulose, lignin, wax, chitin, pectin, β-glucan, inulin and oligosaccharides, which are usually divided into two categories: water-insoluble dietary fiber and water-soluble dietary fiber. Dietary fiber is indispensable for a healthy diet. Fiber plays an important role in keeping the digestive system healthy. At the same time, taking enough fiber can also prevent cardiovascular diseases, cancer, diabetes and other diseases. Fiber can clean the digestive wall and enhance the digestive function. At the same time, fiber can dilute and accelerate the removal of carcinogens and toxic substances in food, protect the fragile digestive tract and prevent colon cancer. Fiber can slow down digestion and excrete cholesterol as quickly as possible, so it can control blood sugar and cholesterol at the best level.