Nutrition is a branch of biology, which studies the relationship between nutrition and biological health. It is also a science to study human nutrition law and its improvement measures. Specifically, it is a science that studies the law of food utilization and metabolism and scientifically determines the amount of nutrients needed by the human body. In its development process, nutrition not only includes the changes of food entering the body, such as participating in biochemical reactions and combining with tissues and cells; It also includes instructing people how to choose food to ensure the normal growth, development and reproduction of the body. Therefore, nutrition has not only biological significance, but also social and economic significance.
Nutrition and nutrition are two concepts. Nutritionists interpret nutrition as the interaction and balance between nutrients and other substances in food and health and diseases, as well as the process of ingestion, digestion, absorption, transportation, utilization and excretion of substances. It is a comprehensive physiological process, not a specific nutrient. Nutrients are an important material basis for human survival and maintaining human health, but rich nutrients may not bring real health to human body. If we don't pay attention to our eating behavior and the types of food are unreasonable, it will easily lead to the lack or excess of some nutrients and some nutritional diseases. The whole process of human life is inseparable from nutrition, and reasonable nutrition can enhance the body's resistance to diseases and achieve the purpose of prolonging life. For example, if the human body is compared to a building, nutrition is equivalent to various materials of the building. If the materials are insufficient to cut corners or the quality of the materials is unqualified, the building will definitely be unstable. Similarly, if malnutrition or poor nutritional quality, this person will certainly not be very healthy. In addition, the relationship between them is complementary, and adequate and balanced nutrition can help the body enhance its immunity and ability to resist diseases. And a healthy body is the premise of absorbing nutrition. For example, the body has a fever, people's body temperature rises, the activity of digestive enzymes decreases, they can't digest food well, and their appetite decreases, let alone absorb nutrients. Nutrition affects people's growth, intelligence, longevity, rehabilitation and the growth of the next generation, and even affects the prosperity of a nation and a country.
A balanced diet is an inevitable requirement for improving people's living standards. It refers to a diet made by choosing a variety of foods and matching them properly. This diet can meet people's needs for energy and various nutrients, so it is called a balanced diet. Generally speaking, it refers to the establishment of a balanced relationship between dietary nutrition supply and physiological needs of the body in four aspects at the same time: amino acid balance, energy and nutrient balance, acid-base balance and the balance between various nutrients intake. This is conducive to the absorption and utilization of nutrients.
We know that food can be divided into two categories, one is animal food, including meat, fish, poultry, eggs, milk and its products; The other is plant food, including grains, potatoes, vegetables, fruits, beans and their products, sugars and bacteria and algae. Different kinds of food have different nutrients: animal food and beans contain high-quality protein; Vegetables and fruits contain vitamins, mineral salts and trace elements; Cereals, potatoes and sugars contain carbohydrates; Edible oil contains fat; Liver, milk and eggs contain vitamin A; Liver, lean meat and animal blood contain iron. These nutrients can cooperate and restrict each other. For example, vitamin C can promote the absorption of iron; Fat can promote the absorption of fat-soluble vitamins A, D, E and K; Trace element copper can promote the transportation and storage of iron in the body; Carbohydrate and fat can protect protein and reduce its consumption; Phosphoric acid, oxalic acid and phytic acid will affect the absorption of calcium and iron. Therefore, only eating a compound diet with reasonable dietary structure can satisfy children's intake of food nutrition.
In order to make people choose food more reasonably and mix it reasonably, nutritionists found that all kinds of food can be divided into five categories through research, and designed a balanced diet pagoda.
The pagoda of balanced diet is divided into five layers, including the main types of food we should eat every day.
First floor (ground floor): cereal. Including rice, flour and miscellaneous grains. Mainly provide carbohydrates, protein, dietary fiber and B vitamins. They are the main source of energy in the diet, and it is better to eat a variety of grains mixed than to eat one alone. Everyone should eat 350-500 grams a day.
Second floor: fruits and vegetables. It mainly provides dietary fiber, minerals, vitamins and carotene. Vegetables and fruits have their own characteristics and can't completely replace each other. You can't just eat fruits without vegetables. Generally speaking, red, green and yellow vegetables and dark yellow fruits are rich in nutrition, so eat more dark vegetables and fruits. Eat 400-500 grams of vegetables and 0/00-200 grams of fruit every day.
The third floor: fish, shrimp, meat and eggs (meat includes animal meat, poultry meat and internal organs). Mainly provide high-quality protein, fat, minerals, vitamins A and B vitamins. They have different nutrients. Eat 150~200 grams every day.
The fourth floor: milk and beans. Milk mainly includes fresh milk, milk powder and so on. Besides being rich in high-quality protein and vitamins, it is an excellent source of natural calcium with high calcium content and high utilization rate. Beans are rich in high-quality protein, unsaturated fatty acids, calcium and vitamins B 1, B2, etc. Drink 250-500g fresh milk and eat 50- 100g beans and bean products every day.
The fifth layer (spire): grease. Include vegetable oil, etc. Mainly provides energy. Vegetable oil can also provide vitamin E and essential fatty acids. No more than 25 grams per day.
It should be pointed out that for everyone, the five kinds of food needed every day on the balanced diet pagoda are irreplaceable. On the same floor of the pagoda, all kinds of foods contain roughly the same nutrients. So in the normal diet, we can often replace each other. In a sense, such mutual substitution is very reasonable and should be advocated, because it can enrich the diet. The more varieties you eat, the more comprehensive your nutrition will be. For intake. You can adjust it slightly according to your actual situation, and you don't have to eat word for word according to the amount said on the pagoda, because the most important and core thing of the diet pagoda is to include all kinds of food in the pagoda every day. As long as you always follow the approximate proportion of various foods in the pagoda, you can basically achieve a balanced diet.