Carbohydrates are the body’s main source of energy and are widely found in grains, beans and fruits. Different foods contain different amounts of carbohydrates, for example, 100 grams of oats contains 60 grams of carbohydrates, while 100 grams of apples contain 12 grams of carbohydrates. In addition to grains, beans and fruits, vegetables and meat also contain carbohydrates, but in small amounts. For example, 100 grams of beef contains only 1.2 grams of carbohydrates. What we usually call staple food refers to foods with high carbohydrate content, such as white noodles (73 grams of carbohydrates/100 grams), brown rice (77 grams of carbohydrates/100 grams), oats (60 grams of carbohydrates/100 grams) g) etc. There are 4 calories per gram of carbohydrates.

Carbohydrates can be divided into simple carbohydrates (Simple Carbohydrates) and complex carbohydrates (Complex Carbohydrates). Simple carbohydrates contain only 1 to 2 sugar molecules. Among them, those containing one sugar molecule are called monosaccharides, such as glucose; those containing two sugar molecules are called disaccharides, such as sucrose and lactose. Complex carbohydrates contain 3 or more sugar molecules. Among them, those containing 3 to 10 sugar molecules are called oligosaccharides; those containing hundreds or thousands of sugar molecules are called polysaccharides. Most oligosaccharides cannot be absorbed by the human body, but they are food for probiotics in the intestines; polysaccharides are divided into starch (absorbable) and dietary fiber (non-absorbable) based on whether they can be absorbed by the human body.

In short, food is composed of carbohydrates and other nutrients (proteins, fats, vitamins, minerals and water). Carbohydrates are composed of several sugar molecules.