You need energy to be physically active and for your body to grow and function. Carbohydrates, fat and protein provide the energy from food. The body's most readily available source of energy. Each gram of carbohydrate provides 4 calories of energy. The main forms of carbohydrate are sugars and starches.
Sugars are simple carbohydrates.
Starches, such as breads, cereals and pasta, are complex carbohydrates. Fat provides 9 calories per gram, more than twice as much energy as protein and carbohydrate. A form of carbohydrate which your body can't digest. Fiber helps your digestive tract work. A major component of all body tissue.