Even better, since carbohydrates have only four calories a gram, while fat has nine, you can eat over twice the amount of carbohydrate based food than fat based food and still get fewer calories. The body turns almost all carbohydrates into glucose, the primary fuel of the body and the dominant sugar in the blood. Simple carbohydrates are sugars. It doesn't matter if they come from fruit, vegetables or honey, they all have about the same nutritional and caloric value. Dietary sugars are broken down into their simplest form, glucose and fructose, and are absorbed into the cells for energy.
Complex carbohydrates are glucose molecules usually combined with fiber, cellulose and starches.
They provide more nutritional variety than simple carbohydrates and are a major source of dietary fiber, which is not found in animal products. Soluble fiber is an important factor in lowering blood cholesterol, but it has become an increasingly smaller part of the typical American diet, mostly due to the popularity of white flour, which has very little fiber. Whole wheat flour and other whole grains are rich in fiber and complex carbohydrates. Two slices of whole wheat bread has about 140 calories, while a soft drink has about 150. While some sugar is not harmful, we can get all of the sugars we need from fruits, vegetables and whole grains.