Learn to use the knowledge of food exchange portions to diversify and structure your diet and control total calories. Food exchange is the weight of various types of food containing 90 kcal, so it is easy to understand the relationship between calories and weight. Usually, commonly used foods are divided into eight small categories: 90 kcal = 10 grams of cooking oil (15 grams of nuts) = 25 grams of raw staple foods = 50 grams of meat (80 grams of fish and shrimp) = 60 grams of eggs = 100 tofu (north) = 160 ml of fresh milk = 200 grams of fruit = 500 grams of green leafy vegetables. It is best to include the above eight food groups in your diet throughout the day. The principle of exchange is between the same kind, for example, exchanging pasta for rice, fish and shrimp instead of pork, etc. This will help enrich the variety of food without causing too much or too little calorie intake. It is not advocated to exchange between different types of food, such as exchanging vegetables for staple foods, meat dishes for staple foods, etc.