Carbohydrate is a word that describes sugar. Other terms include saccharide, monosaccharide, disaccharide, polysaccharide, glycogen, starch, cellulose, soluble fiber, non-soluble fiber, structural carbohydrate and non-structural carbohydrate.
All sugar comprises the same three elements: carbon, hydrogen and oxygen. So, for example, glucose and fructose are both C6 H12 O6, but glucose has a ring of 6 carbons, and fructose is a ring of 5 carbons. This difference is incredibly significant in how the body uses these sugars, with fructose more efficient in creating body fat but can exhaust the cell to death.
The purpose of feeding carbohydrates is twofold. One is to restore the lost glycogen in the muscles and liver when the stored glucose fuels movement and metabolism, a continuous process throughout life. The second is to create body fat for the upcoming winter. There is no other reason for consuming carbohydrates.
The hormone insulin escorts glucose (not fructose) from the gut wall to all cells. Unescorted glucose in the blood (blood glucose) damages vessel walls. Insulin is essential for all of this and, in addition, prevents the body from using any body fat for fuel. I call it the bully on the playground.
You can learn more about carbohydrates in the nutrition course included in the membership.