Protein is only a daily non-staple food, not the main source of daily calories, but the main raw materials of human organs, hormones and immune substances. Therefore, protein cannot be reduced. The daily demand for protein is about 80 grams per person, and there are many people who do a lot of exercise, such as bodybuilders. Among animal proteins, protein of milk and eggs is the best among all foods in protein, because it is the easiest to digest and has complete amino acids, so it is not easy to cause gout attacks. The protein content of egg yolk is slightly higher than that of protein, but an egg yolk can contain as much as 300 mg of cholesterol. Even people without heart disease should not eat more egg yolk. protein's cholesterol content is 0; Egg yolk contains a lot of oil. Usually, we don't see oil in the egg yolk, but when you bake the egg yolk in the microwave oven, you will find that a lot of oil can flow out. You can also see the oil in the salted egg yolk. The calorie of egg yolk is six times that of protein, so egg yolk is also a high-calorie food, and it is a food that people who need to lose weight need to go on a diet. Milk not only supplements protein, but also provides abundant calcium, which can prevent calcium deficiency. Skim milk powder has the highest calcium content and almost no fat, so milk made from skim milk powder is the best protein and calcium source for adults to keep slim. The best vegetable protein is soybean protein, which contains 35% protein and is easy to absorb. Therefore, soy protein has always been the main source of protein for vegetarians. Bean products can lower cholesterol and fight cancer. Soybean protein is rich in isoflavones, which are hormone-like compounds that can inhibit the growth of tumor cells caused by hormone imbalance. Besides, edible fungi are the main source of protein for slimming people.