Food: Food refers to all kinds of finished products or raw materials for human use or drinking, and is the most basic substance for human survival and development. The so-called food actually refers to the food with rich nutrition and diverse functions, which can maintain, improve or regulate the metabolic function of human body.

Fundamental terms of food industry defines food as substances that can be eaten or drunk by human beings, including processed foods, semi-finished products and unprocessed foods, excluding tobacco or substances that are only used as medicines.

As we all know, food can be divided into two categories: alkaline food and acidic food. People must mix acidic and alkaline foods to maintain the balance of blood PH in the body. The so-called acidic and alkaline foods are not identified by taste or taste, but mainly by the chemical elements contained in the food being absorbed and oxidized by the human body.

Generally, acidic foods contain more nonmetallic elements such as nitrogen, sulfur and phosphorus, while alkaline foods contain more metallic elements such as sodium, potassium, calcium and magnesium. Either the taste is sour or the food is sour.

digestive absorption

Small intestine is the main place for digestion and absorption. Food is chemically digested by pancreatic juice, bile and intestinal juice and mechanically digested by small intestine, and various nutrients are gradually decomposed into simple absorbable small molecules and absorbed in small intestine. Therefore, after food passes through the small intestine, the digestion process has been basically completed, leaving only indigestible food residues, which enter the large intestine from the small intestine.