From the point of view of nutrition, it can keep the balance between nutritional demand and dietary supply, heat energy and various nutrients can meet the needs of human growth and development, physiology and physical activity, and a diet with appropriate proportions of various nutrients is called a balanced diet. To achieve a balanced diet, it is necessary to start with a reasonable table diet for everyone and every family, that is, to eat a variety of foods. There are nearly 50 kinds of essential nutrients for human body, all of which are indispensable. No natural food can satisfy all the nutrients the human body needs. Therefore, the diet must be composed of a variety of foods. Two thousand years ago, Su Wen in Huangdi Neijing put forward the principle of "five grains for nourishment, five fruits for help, five livestock for benefit and five vegetables for filling", which reflected the requirements of food diversification and balanced diet. According to the nutritional characteristics of food, it can be divided into five categories: the first category is cereals, potatoes and miscellaneous beans, which mainly provide carbohydrates, protein and B vitamins, and are also the main sources of heat energy and protein in China's general diet; The second category is animal food, including meat, poultry, eggs, milk, fish and so on. , mainly providing protein, fat, dietary fiber, minerals, vitamins A and B; The third category is soybeans and bean products, which mainly provide protein, fat, dietary fiber, minerals and B vitamins; The fourth category is vegetables and fruits, which mainly provide minerals, vitamin C, carotene and dietary fiber; The fifth category is pure heat energy food, including animal and vegetable fats, edible sugar and wine, starch and so on. , mainly providing heat energy.

Second, the principle of nutritious diet

Eating real food is easier said than done, because the market is full of so-called "modern foods" that look like food, such as fresh fruit iced yogurt, breakfast cereal biscuits and non-dairy cream, which will make your great-grandmother feel at a loss. So, I suggest you ask your great-grandmother to help you judge. The food she can recognize may be the real food.

2. Avoid processed foods that claim to be healthy. These foods are usually over-processed, and the so-called health promotion is often not fully believed. For example, margarine was one of the first processed foods that claimed to be healthy, but it turned out to be likely to cause heart disease.

3. Avoid foods containing more than five unfamiliar ingredients. Although these ingredients may not be harmful, if a food contains so many unfamiliar ingredients, it is enough to prove that the food is over-processed.

4. Try to stay away from the supermarket. In the fresh vegetable market, you won't encounter processed foods such as "high fructose corn syrup", and you won't encounter foods that were shipped from far away long ago. The fresh vegetable market provides fresh and healthy food.

5, mainly eat vegetables and fruits, eat more leaves. Scientists have not yet reached an agreement on why vegetables are good for health, but they all agree that vegetables are really good for human health. In addition, eating more vegetables can help you greatly reduce your calorie intake.