Nutrition is the material basis to ensure human health and longevity. The function of human organs and the normal metabolism of tissues depend on essential nutrients, which are obtained through a reasonable diet. Nutritional factors have a considerable impact on the prevention and treatment of diseases and the aging process, especially the health status in later years. People with good nutrition can effectively delay aging. For example, at the age of 60, some people show weakness, instability, fatigue, slowness, shortness of breath and insensitivity. However, some people are still like "young people" after 80 years old. Therefore, the degree of physiological or functional aging in old age, in a sense, depends on the nutritional status rather than the age of survival, that is, eating long life. Insufficient nutrition will make people physically decline, easily get sick and accelerate aging. Overnutrition will bring troubles to people, such as obesity accompanied by hypertension, coronary heart disease, diabetes, arteriosclerosis and so on. At present, the nutritional status of urban and rural residents in Shanghai is characterized by the coexistence of undernutrition and overnutrition, which leads to the coexistence of some diseases (obesity, cardiovascular diseases, etc.) related to undernutrition and overnutrition. If it develops naturally, malnutrition will gradually decrease, while diseases related to overnutrition will gradually increase. In view of this situation, nutritionists put forward a reasonable diet. So, how can we make a reasonable diet? The first is comprehensive balance, that is, eating everything, not picky eaters, not partial eclipse. As we all know, no single natural food can provide all the nutrients needed by the human body. Therefore, a reasonable diet must consist of a variety of foods in order to achieve a balanced diet. According to its composition, food can be divided into five categories. The first category is cereals and potatoes, which mainly provide carbohydrates, protein and B vitamins, and are the main sources of dietary energy in China. The second category is animal foods, such as meat, poultry, eggs, fish and milk, which mainly provide protein, fat, minerals, vitamins A and B and essential fatty acids. The third category is soybean and its products, which mainly provide protein, fat, cellulose, minerals and B vitamins. The fourth category is vegetables and fruits, which mainly provide cellulose, minerals, vitamin C and carotene. The fifth category is pure heat energy food, including animal and vegetable fats, various edible sugars and alcohol, which mainly provide heat energy and essential fatty acids. Nutritionist's suggestion: 1. Appropriately increase animal food, improve the quantity and quality of dietary protein, but prevent excessive consumption. 2. Change the structure of animal food, give priority to pork, increase the intake of poultry, aquatic products and milk such as chickens and ducks, and prevent excess fat, especially saturated fat. 3. Increase the intake of bean products and improve the quantity and quality of dietary protein. 4. Stabilize the food intake and maintain the fine tradition of "five grains for nourishment" in China, but limit the intake of sucrose to prevent excessive calorie intake. 5. Ensure the intake of vegetables. It is best for everyone to consume about 500 grams of various vegetables every day to ensure the source of certain vitamins, minerals and cellulose. 6. Edible fungi should be included in the diet structure, because they contain high protein, appropriate proportion of essential amino acids and various trace elements, which can improve the immune function of the body. Diet should be diversified, not partial eclipse. The elderly should pay attention to eating more beans and bean products, milk, lean meat, shrimp skin, eggs, kelp, vegetables and so on. Don't eat too salty and sweet. The average daily salt intake was 10g (5g for patients with hypertension). Partial eclipse can lead to various nutrient-related diseases. If you eat too much animal fat, salt and sugar and lack fresh vegetables and fruits, it is often a risk factor for hypertension, coronary heart disease and stroke. When choosing food, we should pay attention to freshness, eat it within one day as much as possible, and eat less overnight dishes, even if there is a refrigerator. Pay attention to storing dry food to avoid mildew. When buying packaged cooked food, pay attention to the shelf life and delivery date on the packaging bag. Maintain the characteristics that China's diet is mainly based on plant food, supplemented by animal food, and the source of heat energy is mainly grain, so as to avoid the disadvantages of excessive fat and high heat energy brought about by western dietary patterns. The second is the right amount. Being too fat or too thin is not good for your health. The viewpoint of "not having enough to eat" is put forward by previous health care experience, and its purpose is to make the diet moderate, the hunger moderate, and the intake and consumption of nutrients such as heat energy and protein adapt to avoid obesity or emaciation. Regular weighing is a common method to measure whether the diet is moderate or not. The third is that three meals should be reasonable. It is necessary to establish a reasonable diet system, avoid overeating and advocate not eating or eating less snacks. In the heat energy distribution of three meals a day, breakfast accounts for 30% of the total heat energy of the whole day, lunch accounts for 40%, and dinner accounts for 30%. It has been tried that eating 2000 calories every morning has little effect on weight; Eating so many calories at night will put on weight. Others have done such an experiment, two groups of people eat the same food, one group eats at 7 am; The other group eats at 5: 30 pm (each person only eats once a day). As a result, people who eat in the morning generally lose weight, while those who eat at 5: 30 pm continue to gain weight. In addition, scientists also found that the number and time of meals have a great influence on serum cholesterol levels, and multiple meals can keep serum cholesterol at a low level. With the same amount of cholesterol food, the blood cholesterol level of eight meals is lower than that of three meals; 6 meals are less than 1 meal. At present, in daily life, people are busy with work during the day, and the Chinese food at breakfast is so-so, and the whole family is reunited at night. Chicken, duck, fish and eggs are available on the dining table. 70% of the calories consumed in a day are concentrated in dinner, which makes blood lipids soar, leading to arteriosclerosis and coronary heart disease. In addition, when people are over middle age, the body's ability to handle sugar is reduced, which is characterized by decreased glucose tolerance and excessive calorie intake at dinner, which is easy to induce diabetes. According to the survey, before the age of 40, diabetes is rare. After the age of 40, the incidence of diabetes increased by about 10% almost every10 year. The survey also found that the incidence of diabetes in urban residents is significantly higher than that in farmers, which is related to the bad eating habits of urban residents, such as "eating less breakfast, eating poorly at lunch, eating enough at dinner and drinking alcohol". Therefore, nutritionists at home and abroad advocate that it is indeed a very important health care measure to satisfy breakfast, eat lunch and control dinner. The fourth is that midnight snack should not be too oily and full. As the saying goes, "Don't eat too much delicious food, and overeating makes people sick", which is scientifically justified. Overeating, especially eating a large number of high-protein and high-fat diets such as fat meat, ribs, fat chickens and fat ducks. Especially after dinner, I am busy sleeping, which makes the pancreatic exocrine in the human body too active and pancreatic juice overflows; At the same time, overeating will make the mucosa of stomach and duodenum hyperemia, duodenal papilla edema, lead to self-digestion of pancreas, and cause acute hemorrhagic circular pancreatitis. Patients often go into shock because of severe pain, and some die before they can be rescued.