What Are the Differences Between Starch, Fiber & Sugar?

When it comes to carbohydrates, there are simple forms and complex forms. Carbohydrates power the body as the primary energy source and should make about 40 to 60 percent of a person's daily nutritional intake. The various parts of carbohydrates -- starch, fiber and sugar -- have distinct jobs in the body. Carbohydrates are found naturally in fruits, vegetables and grains. They can also be found in processed foods of breads, soda and candy.

Fiber is a complex carbohydrate which can be soluble or insoluble, meaning easily or not easily dissolved. Fiber helps slow down the digestion process which allows food to slowly break down and not become sugar as quick. They help the body maintain blood sugars levels, so they will not spike. Insoluble fiber such as wheat bran, vegetables and whole grains work to add bulk to the stool and do not break down in the body until they meet various bacteria in the intestines.

Starch is another form of a complex carbohydrates. Unlike fiber, it is slowly digested by the body and becomes blood glucose that is absorbed into the bloodstream. Starch is the main dietary source of carbohydrates for the body. It can be found naturally in foods such as beans, grains of rice and wheat, as well as potatoes. Processed foods containing starch include pasta, breads and cereals.

Sugar is considered a simple carbohydrate. It is the basic building block of molecules for every type of carbohydrate. Unlike fiber and starch, it breaks down quickly and easily into glucose which is used by the body as a primary energy source. This simple form can be found in fruits and vegetable but are also in a variety of foods such as candies and soda pop.

While it appears that these three parts are separated, within food groups two or all three can appear in the same food source. A raspberry has a high sugar content along with high fiber content, which means the sugar is released quickly, but the fiber content will slow down its progress through the body. Breads are starches, but they breakdown as quickly as sugar, spiking sugar levels. Finding the best balance of the parts of carbohydrates takes the help of a nutritionist.