With the increase of age, the physiological function of the body will gradually decline. Improving nutrition, preventing premature aging and senile diseases and prolonging life span have become important topics in gerontology. The nutritional needs of the elderly have the following characteristics:

(1) heat demand. With the decrease of physical activity and metabolic activity, the consumption of calories also decreases accordingly. Generally, for the elderly who don't have much activity, 6276~8368 kilojoules (1500~2000 kilocalories) per day is enough. If you continue to eat unnecessary high-calorie meals, you will be overweight, accompanied by some common senile diseases, such as coronary heart disease and high blood pressure, which will affect your health.

(2) The needs of protein. In principle, it should be high quality and low quantity. Because catabolism is the main metabolic process of the elderly, rich protein is needed to compensate for the consumption of tissue protein. Protein with high biological value should be supplied as much as possible, accounting for more than 50% of the total intake of protein, such as beans and fish. On the contrary, too much protein will aggravate the burden of digestive function and renal function of the elderly. If you eat too many eggs and animal offal, it will increase the synthesis of cholesterol in your body, which is not good for your health.

(3) the need for carbohydrates. Carbohydrates include starch, sucrose, maltose, lactose, fructose, glucose, cellulose and pectin. Except cellulose and pectin, the rest can be absorbed and utilized. They are the main substances that provide heat energy for human body. Sugar in food mainly comes from starch in grains. In addition, sugar, fruits and vegetables also contain a small amount of carbohydrates. The amount of carbohydrates in the diet of the elderly is lower than that of young people, which is about 300 ~ 400g, or accounts for 60%~70% of the total daily energy. For the elderly over 60 years old, the daily total heat supply is about 350 1 1.7 1 kilojoule (8368kcal), and the carbohydrate supply should be 300-350g. The carbohydrate supply of the elderly should be appropriately adjusted according to their personal characteristics. Obese elderly people should limit their intake of staple food and increase their activity. When you are hungry, you should supplement fruits and vegetables. On the other hand, elderly people who are not accompanied by obesity and have a large momentum of physical activity can appropriately increase the supply of staple food. At the same time, the diet of the elderly should pay attention to the supply of a certain amount of cellulose and pectin, which can stimulate intestinal peristalsis. The motor function of the elderly is weakened, the muscle tension of the intestinal wall is reduced, and constipation is easy. A diet lacking in fiber will aggravate constipation symptoms in the elderly.

(4) the need for fat. The fat tissue of the elderly will gradually increase, and too much fat is not conducive to the cardiovascular system, digestive system and liver. But if you eat too little fat, it will affect the absorption of fat-soluble vitamins, so you need to eat a certain amount of fat to keep a balanced diet. The general principle is to try to choose fats with more unsaturated fatty acids and reduce the contents of saturated fatty acids and cholesterol in the diet, that is, eat more vegetable oils such as peanut oil, soybean oil, vegetable oil and corn oil, and eat less animal fats such as lard and ghee.

(5) the need for inorganic salts. Inorganic salts participate in many main physiological functions in human body, so it is of great significance to supply inorganic salts to the elderly reasonably for their health and longevity. The old people's ability to use and store calcium is reduced, and it is easy to have a negative calcium balance. Long-term and sustained negative calcium balance is an important reason for the increase of osteoporosis incidence in the elderly, especially in women. In addition to insisting on proper exercise, receiving more sunlight and ensuring the intake of calcium in food at all times (at least 600 mg of calcium every day) is very beneficial to prevent osteoporosis. Milk is rich in calcium and easy to absorb, so it is a good food for the elderly to supplement calcium. For sodium salt, the elderly should be appropriately restricted. Usually, the daily salt intake is 5 5~ 10/0g, and should not exceed 8g. Potassium mainly exists in intracellular fluid, the catabolism of the elderly is often greater than the anabolism, the intracellular fluid decreases, and the potassium content in the body tends to decrease. Therefore, we should ensure the supply of potassium in the diet, and supply 3~5 grams a day can meet the needs. Lean meat, beans and vegetables are rich in potassium.

(6) the need for water. The muscles of colon and rectum in the elderly are atrophied and their defecation ability is poor. In addition, the mucus secretion in the intestine is reduced, and the stool is easy to be secret. It is generally believed that the amount of drinking water for the elderly is about 2000 ml per day to keep the urine volume around 1500 ml.

Due to the above physiological needs, the elderly need to supplement enough nutrition. The formation of good eating habits is the basic guarantee of good health. According to the physiological characteristics of the elderly, it is more appropriate to eat less and eat more, and overeating is harmful. Nor should we be too hungry or too full. Seven-point fullness is the most appropriate, and you should chew slowly when eating. Meals should strive to be good in color, flavor and shape and rich in nutrition. When cooking, chop it up and cook it soft, because the chewing and digestion ability of the elderly is slightly poor. The diet temperature should be appropriate, and it is not advisable to eat foods that are too sticky, too sweet, too sour, too salty, too greasy or fried.