Nut is a classification of closed fruit, with hard skin and 1 seed or multiple seeds. Such as chestnut, almond and other fruits. Nuts are the essence of plants, which are generally rich in nutrients and high in protein, oil, minerals and vitamins, and have excellent effects on human growth and development and physical fitness.

Nuts, also known as shell fruits, are mostly cotyledons or endosperm of plant seeds, which have high nutritional value. Time magazine once selected it as one of the top ten nutritious foods for modern people. Nuts are generally divided into two categories: one is tree nuts, including almonds, cashews, hazelnuts, walnuts, pine nuts, chestnuts, ginkgo biloba, pistachios, macadamia nuts and so on; The other is seeds, including peanuts, sunflower seeds, pumpkin seeds, watermelon seeds and so on.

Nuts contain 36.0% protein, 58.8% fat, 72.6% carbohydrate, vitamins (vitamin B, E, etc.), trace elements (phosphorus, calcium, zinc, iron), dietary fiber, etc. In addition, it also contains monounsaturated fatty acids and polyunsaturated fatty acids, including essential fatty acids such as linolenic acid and linoleic acid.