In general, onions are a common vegetable that can provide the body with carbohydrates and other nutrients when consumed in moderation. Vegetables usually refer to plants or mushrooms that can be made into food after cooking, and are essential to a person’s daily diet. Onions belong to the category of vegetables, moderate consumption for the human body has a certain nutritional value. Onions contain some carbohydrates, but also contains some protein, dietary fiber and flavonoids. Every 100 grams of onion contains about 40kcal, of which 9 grams of carbohydrates, 1.1 grams of protein, 0.2 grams of fat, vitamin C8 mg, 24 mg of calcium, 0.6 mg of iron. Moderate consumption can provide the body with energy and the above nutrients. In addition, if there is an allergy to onions, it is not recommended to consume them, so as not to cause a serious allergic reaction.