Our problems are not caused by lack of medical care and medicine. Dietotherapy is popular now. If we are constipated, we should eat more foods rich in cellulose, which is a polysaccharide compound. Dietary fibres includes crude fiber, semi-crude fiber and lignin. Function of cellulose: ① Help E.coli in intestine to synthesize multivitamins. ② Cellulose has a small specific gravity and a large volume, occupying a large space in the gastrointestinal tract, which makes people feel full and is beneficial to lose weight. ③ Cellulose has a large volume, which can stimulate the gastrointestinal tract, increase the secretion of digestive juice, enhance gastrointestinal peristalsis, and prevent and treat diabetic constipation. ④ High fiber diet can slow down the absorption of sugar by delaying gastric emptying, changing intestinal transit time and forming soluble fiber gel in the intestine. It can also reduce the secretion of intestinal hormones such as gastric inhibitory peptide or glucagon, reduce the stimulation to islet B cells, reduce insulin release, increase the sensitivity of peripheral insulin receptors, and thus strengthen glucose metabolism. ⑤ Recent studies have proved that high fiber diet can increase insulin receptor binding on monocytes of patients with type I diabetes, thus saving insulin demand. It can be seen that eating a high-fiber diet for diabetic patients can not only improve hyperglycemia, reduce the dosage of insulin and oral hypoglycemic agents, but also help to lose weight and prevent constipation.