Heat energy is to meet the energy needs of human life activities, growth and development, and repair pathological conditions. Because of the vigorous growth and frequent activities of middle school students, the demand for heat energy greatly exceeds that of primary school students, and the daily heat supply should be 0.96 ~■1.17×107 joules. Heat energy is not a simple nutrient, but biochemical energy released by digestion of carbohydrates, protein and fats in food.
Carbohydrate is the main source of human heat. China people's carbohydrates mainly come from rice and wheat. The intake of carbohydrates in daily diet should account for 60% of the total calorie supply.
Protein is the material basis of life and youth development. Besides providing heat energy, protein has many extremely important functions. Lack of protein can cause growth retardation, emaciation, anemia, and difficult wound healing. , and seriously affect intelligence. The daily protein supply of middle school students is 80 ~ 90g. Among them, automatic physical food and beans are preferably 1/2 or 1/3.
When it comes to being fat, many female students are very sensitive and regard being fat as the enemy of their physical beauty. In fact, eating too much fat will certainly cause obesity, cardiovascular diseases and diabetes, but if we don't pay attention to the necessary intake of moderate fat, the result will also affect the absorption of some fat-soluble vitamins, which will have an adverse impact on growth and development. Generally speaking, fat in a normal diet accounts for 35% of the total calorie supply. Daily high-fat foods include lard, vegetable oil, meat, eggs, peanuts, melon seeds and other hard fruits.
Vitamins are trace organic substances necessary for life, growth and activities. The main types are vitamins A, B 1, B2, C and D, which play an important role in the growth and development of teenagers. If these vitamins are lacking, it will cause developmental retardation, night blindness, dry skin, beriberi, oral ulcer, scurvy and rickets. These vitamins are stored in different foods, and students with partial eclipse habits often suffer from the lack of certain vitamins.
Inorganic salts mainly include calcium, phosphorus, iron, zinc, sodium, potassium and magnesium. Calcium and magnesium are the main components of teeth and bones, and insufficient calcium supply will affect bone development. Common foods with high calcium content are vegetables, grains and beans. Phosphorus is widely distributed in food and is generally not lacking. Iron is the raw material for hematopoiesis. Iron deficiency can lead to anemia. Female students who come to menstruation have lost too much blood and need iron supplementation. Good sources of dietary iron are animal liver, egg yolk, beans and some vegetables.