Protein – an important substance for life activities. Protein is an important component of the body’s tissues and organs, and it is especially important for children during their growth and development. Protein is also involved in the regulation of important physiological functions. Protein in food can be divided into two categories: plant protein and animal protein. Among plant proteins, cereals contain about 10% of protein, although the content is not high, but because it is the staple food of people, it is still the main source of dietary protein. Soybeans are rich in protein, up to 36-40%, with a reasonable ratio of amino acids and high utilization rate in the body, making them a very good source of protein among plant proteins. Eggs contain 11-14% protein and are an important source of high quality protein. Milk (milk) generally contains 3-3.5%, and is the best source of protein for infants and children. Meat includes poultry, livestock and fish muscle, fresh meat contains 15-22% protein, its nutritional value is higher than plant protein, is an important source of human protein. In order to improve the quality of protein in food, try to ensure that there is a certain amount of high-quality protein in the diet, generally require animal protein and soy protein accounted for 30-50% of the total dietary protein.