Maintaining the acid-base balance in the human body depends on the acidity and alkalinity of the ingested food and the adjustment of the acid-base balance by the excretory system. The acidity and alkalinity of food refers to the result of metabolism in the body after digestion and absorption. If there are more phosphate, sulfate and chloride ions produced after food metabolism, it is easy to form acid in the body and produce acidic reaction. If more sodium ions, potassium ions, magnesium ions and calcium ions are produced, it is easy to produce more alkali in the body and form an alkaline reaction. This is related to the mineral content in food. Generally speaking, foods containing more minerals such as sulfur and phosphorus are acidic foods; Foods containing more minerals such as potassium, calcium and magnesium are alkaline foods. Some foods, such as refined oil, sugar, starch, etc., basically do not have the above two kinds of elements, so they are neutral foods, and these foods do not affect the pH of body fluids. Therefore, the so-called acidic food can't be understood as sour food, and the fruits with sour taste, such as tomatoes, oranges, hawthorn, bayberry, etc., will have an alkaline effect on the human body after being metabolized in the body.

Alkaline food: tofu, milk, celery, potatoes, bamboo shoots, mushrooms, carrots, kelp, mung beans, bananas, watermelons, strawberries and so on.

Weakly alkaline food: potato, cabbage, Lu Xun, bamboo shoots, peas, squash, lotus root, radish stains, tofu, apples, pears, bananas, pineapples, cherries, peaches, and cows.

Strongly alkaline food: milk, tomato, cucumber, turnip, carrot, fig spinach, celery, citrus, grape, taro, kelp, raisin, and tender.

Weak alkaline food: red beans, radishes, apples, cabbage, onions, tofu, etc.

Moderately alkaline food: dried radish, soybean, carrot, tomato, banana, orange, pumpkin, strawberry, protein, dried plum, lemon, spinach, etc.

Strongly alkaline foods: grapes, tea, wine, kelp buds, kelp, etc. In particular, natural green algae is rich in chlorophyll, which is a good alkaline health food, while tea should not be overdone, and the best drinking time is in the morning.

Weakly acidic food ham, cream, eggs, snapper, shrimp, abalone, clam, octopus, macaroni, chocolate candy, fried food, onion and fried chicken.

Strong acid food beef, pork, tuna, oyster, cheese, rice, wheat, bread, wine, peanuts, sausage, candy, biscuits and white sugar.

Animal protein contains too much fat, so it is acidic. The order of its acidity from big to small is pork, mutton, beef, chicken and fish.

Strongly acidic food: egg yolk, cheese, west point or persimmon made of white sugar, mullet roe, chaiyu, etc.

Acidic food: ham, bacon, chicken, tuna, pork, eel, beef, bread, wheat, cream, horse meat, etc.

Weakly acidic food: white rice, peanuts, beer, wine, fried tofu, seaweed, clam, octopus and loach.

The so-called acidity and alkalinity of food means whether the inorganic salts in food are acidic or alkaline. General metal elements such as sodium, calcium, magnesium, etc. are alkaline in human body, and foods containing more of these elements are alkaline foods, such as soybean, tofu, spinach, lettuce, radish, potato, lotus root, onion, kelp, watermelon, banana, pear, apple and milk. Some foods contain more nonmetallic elements, such as phosphorus, sulfur, chlorine, etc. After oxidation in the human body, acid radicals with anions are generated, which belongs to acidic foods. Such as pork, beef, chicken, duck, eggs, carp, oysters and shrimps, as well as flour, rice, peanuts, barley and beer.