Keywords: diet, health, rational nutrition, diet, food nutrition
Human life must be maintained by diet. People's quality of life and mental psychology are closely related to diet and nutrition. People's intelligence, physical strength, learning ability, sports ability, disease prevention ability, rehabilitation ability, reproductive ability, life expectancy, height and weight are also inextricably linked with nutritious diet. Unbalanced nutrient intake can cause many diseases. Therefore, reasonable nutrition and balanced diet are important measures to prevent diseases.
Second, the relationship between reasonable nutrition and human health
Nutrition is a process in which organisms constantly absorb necessary substances from the outside to maintain their life activities. For people, nutrition is the whole process of taking food from the outside, digesting and utilizing the substances needed by the body in food to maintain life activities. These substances needed to maintain the normal growth, development and metabolism of the body are called "nutrients".
The basic unit that constitutes the human body is the cell, which constitutes the tissue, the tissue constitutes the organ, and the organ constitutes the human body system. The substances that make up cells come from the nutrients in the food we eat, which are used by the body to nourish the cells in our body. Cell health undoubtedly determines people's health. At present, there are more than forty kinds of nutrients needed by human body, which can be subdivided into seven categories: first, carbohydrates, whose function is to maintain the activity of body cells, mainly come from grains; Second, lipids, whose function is to maintain cell structure and function, mainly come from oils (edible oil, fat, nuts); Third, protein, whose function is to maintain the activity of body cells, mainly comes from fish, meat, beans, eggs, milk and so on; Fourth, vitamins, whose function is to regulate physiological functions, mainly come from vegetables and fruits; Fifth, minerals, whose function is to establish and repair body tissues and regulate physiological functions, mainly come from vegetables and fruits; Sixth, water, whose function is to regulate physiological functions, mainly comes from drinks and soup; Seventh, dietary fiber, whose function is to prevent gastrointestinal diseases and maintain gastrointestinal health, comes from various plant foods.
Reasonable nutrition requires that the percentage of three nutrients in total heat energy is protein 10%~ 15%, fat 20%~30%, and carbohydrate 60%~70%. Protein is an indispensable substance in human tissues, and it is also the main component of various enzymes, antibodies and some hormones. Protein can promote growth and development, maintain the normal permeability of capillaries and supply heat energy. Lack can cause growth retardation, weight loss, fatigue, decreased circulating blood volume, anemia, decreased resistance to infectious diseases, difficult healing of wounds and fractures, and slow recovery after illness. When it is seriously deficient, it can cause malnutrition edema. Fat can supply heat energy, form tissue fat and store fat, supply essential fatty acid (linoleic acid), and fat can also promote the absorption of fat-soluble vitamins. But excessive fat intake can lead to obesity and atherosclerosis. Animal fat contains more saturated fatty acids (except fish), and vegetable oil contains more polyunsaturated fatty acids (except palm oil and coconut oil). Saturated fatty acids can increase serum cholesterol, while polyunsaturated fatty acids can reduce blood cholesterol and triglycerides and reduce platelet adhesion. Therefore, the ratio of saturated fatty acids to polyunsaturated fatty acids (S/P) in the diet is 1∶ 1, which not only takes care of the supply of essential fatty acids, but also prevents some diseases related to fat nutrition (such as coronary heart disease and obesity). Carbohydrate is the food source of heat energy, which can save protein and ensure normal blood sugar, liver glycogen and muscle glycogen to maintain brain activity, liver detoxification and muscle activity. Insufficient carbohydrate intake will lead to insufficient heat energy, slow growth and fatigue, and excessive intake will lead to obesity. Dietary fiber is necessary for human health and substance metabolism. The human body cannot be synthesized, and it can only be supplied by food. Inorganic salts such as calcium, phosphorus, magnesium, potassium and sodium are essential components of the body and have important physiological functions. Iron, iodine, copper, zinc, manganese, titanium, molybdenum, selenium, chromium, fluorine and nickel, which account for less than 0.0 1% of the body weight, are essential trace elements in human body and are closely related to enzymes, vitamins, hormones and nucleic acids.
It is reported that overnutrition and lifestyle diseases have become the number one killers threatening human health. Obesity, hypertension, coronary heart disease and other fatal chronic diseases are eaten by people themselves. The unreasonable diet structure and the invasion of foreign junk food are the biggest reasons for the occurrence of civilized diseases. Nutrition science tells us: "No food can provide all the nutrients our body needs"; There is no bad food, only bad food. Any kind of food can provide some nutrition, and the key is to mix a variety of foods with different characteristics to form a reasonable diet.
All kinds of foods have different nutritional characteristics, and they must be reasonably matched to obtain comprehensive nutrition. China's traditional eating habits are reasonable and have great advantages. Mainly cereals, supplemented by vegetables, low in sugar and high in fiber. However, with the development of economy and the improvement of living conditions, many people tend to eat more animal food. At present, the high incidence of cardiovascular diseases, hyperlipidemia, diabetes and obesity is closely related to this dietary structure.