The different types of whole grain carbohydrates are simple carbohydrates, complex carbohydrates and fiber. The simple carbohydrates that are found in whole grains are sucrose and maltose. Complex carbohydrates, also known as starch, consist of chains of linked-together simple sugars. Fiber, the indigestible type of whole grain carbohydrates, consists of long chains of simple sugars that the human body cannot break down and digest. When carbohydrates are consumed, they are broken down by the body into glucose, which is distributed to the body's cells and gives them energy.
The simple carbohydrate maltose, also called malt sugar, is used by whole grains such as barley to germinate or sprout a seed, and it forms when starch is broken down by the plant for food. Malted barley is made by sprouting the barley and mashing it. This process transforms the starches stored in the barley into maltose. Maltose is also produce when the chains of simple sugars in the whole grain are caramelized during the cooking process. Whole grain carbohydrates that are simple carbohydrates like maltose are quickly digested and provide instant energy to the body.
Simple carbohydrates are also found in natural foods such as fruits and vegetables. Often, foods that are high in simple carbohydrates, such as sucrose or table sugar, are high in calories and low in nutrients. Foods that contain a large amount of simple carbohydrates are processed foods, carbonated soft drinks, baked goods and candy.
Plants store complex carbohydrates in the form of starch. Whole grain carbohydrates that contain starch are rice, oats and whole wheat. Breads and pastas that are made with whole grains will contain starch. Starch is also found in corn, beans and root vegetables such as potatoes.
Carbohydrates are a vital part of a balanced diet. Complex carbohydrates often contain vital nutrients such as B-vitamins, iron and fiber. Eating foods that have whole grain carbohydrates ensures that the body gets the fiber, minerals, vitamins and antioxidants that it needs to be healthy. Whole grain foods such as barley, brown rice and oats contain soluble fiber. Soluble fiber is thought to lower low-density lipoprotein (LDL), or "bad" cholesterol, as well as triglycerides and blood pressure when it is consumed as a part of a balanced diet.
Whole grain foods contain complex carbohydrates and fiber. These types of foods take longer to digest, which leaves a person feeling fuller longer and promotes healthy blood sugar levels. This is why whole grain foods provide energy for a longer period of time when compared with simple carbohydrates.