Hello, human beings eat a variety of foods. Various foods do not contain exactly the same nutrients. In addition to breast milk, any kind of natural food can not provide all the nutrients needed by the human body, a balanced diet must be composed of a variety of foods in order to meet the various nutritional needs of the human body, to achieve rational nutrition, to promote the health of the purpose, and therefore to advocate that people, especially older people should be widely consumed a variety of foods. A variety of foods should include the following five categories:

Guidance:

The first category of cereals and potatoes: cereals, including rice, pasta, grains, etc., potatoes, including potatoes, sweet potatoes, cassava, etc., mainly to provide carbohydrates, protein, dietary fiber and B vitamins.

The second category is animal food: including meat, poultry, fish, milk, eggs, etc., mainly providing protein, fat, minerals, vitamin A and B vitamins.

The third category is legumes and their products: including soybeans and other dried legumes, which mainly provide egg, fat, dietary fiber, minerals and B vitamins.

The fourth category is vegetables and fruits: including fresh beans, roots, leafy vegetables, eggplant and fruits, mainly providing dietary fiber, minerals, vitamin C and carotene.

The fifth category is purely caloric foods: including vegetable and animal oils, starches, table sugar and alcohol, which mainly provide energy. Vegetable oils also provide vitamin E and essential fatty acids.

Cereals are the mainstay of the traditional Chinese diet. As the economy develops and life improves, people tend to consume more animal foods. According to the results of the 1992 National Nutrition Survey, the consumption of animal foods has exceeded the consumption of cereals in some of the more affluent families. This "westernized" or "affluent" diet provides too much energy and fat and too little dietary fiber, which is detrimental to the prevention of some chronic diseases. The reason for proposing cereals as the mainstay of diet is to remind people to maintain the good tradition of diet in China and to prevent the disadvantages of the diets of developed countries. The main purpose of the proposed cereal-based diet is to remind people to maintain the good tradition of our diet and prevent the disadvantages of the diets of developed countries.

Also pay attention to the coarse and fine mix, often eat some coarse and fine, mixed grains and so on. Rice, wheat do not grind too fine, otherwise the surface of the grain contains vitamins, minerals and other nutrients and dietary fiber most of the loss to the bran.

Nutritional value of cereals (a) the structure of the cereal and nutrient distribution of various cereal seeds in addition to the shape of the size is not the same, the structure is basically similar, are made up of the hull, endosperm, germ three main parts, respectively, accounted for the weight of the grain of 13% to 15%, 83% to 87% and 2% to 3%. Hull is the outer shell of the grain, mainly composed of cellulose, hemicellulose, containing high ash and fat. Paste powder layer between the hull and endosperm, containing more phosphorus rich B vitamins and inorganic salts, has important nutritional significance, but in the milling process, easy to fall off with the hull at the same time and mixed into the bran. Endosperm is the main part of the cereal, containing a large amount of starch and a certain amount of protein. Protein is higher near the peripheral part of the endosperm, and the more toward the center of the endosperm, the lower the content. Germ is located at one end of the grain, rich in fat, protein, inorganic salts, B vitamins and vitamin E. Germ is soft and tough, not easy to crush, but in the processing of the endosperm due to easy to be separated from the endosperm and lost.

(2) the characteristics of the nutritional composition of cereals: cereals as a result of the types, varieties and processing methods, as well as different planting areas and growth conditions, the content of its nutrients have certain differences. Cereal protein content is generally 8% to 16%, cereal protein is generally more semi-complete protein. The fat content of cereals is less, about 2%, and the fat of cereals is mostly concentrated in the batter layer and the embryo part of the grain. Cereals have the highest carbohydrate content, mainly starch, an average of 70%. Cereal carbohydrates are the most economical source of energy for the body. The vitamins contained in cereals are mainly B vitamins, such as vitamin B1 and niacin. Most of them are concentrated in the grain embryo, the dextrinous layer and the grain husk. In refined white rice and flour, the vitamin content is significantly reduced because the grain embryo and husk are milled off during processing, e.g., the B vitamins in refined white flour are only 10% to 30% of the original. The mineral content of cereals is about 1.5% to 3.0%, mainly phosphorus and potassium and a small amount of calcium, zinc and iron, etc., mainly in the grain hull and paste flour layer, but mostly in the form of phytates, so the absorption rate is not high. The higher the processing precision of the cereal, the greater the loss of its minerals.