Carbohydrates are also known as starches, sugars, saccharides and polysaccharides depending on their chemical structure. The primary function of carbohydrates in the body is to provide fuel for countless processes, including muscular contraction, brain function and hormone production, and to aid storage of fat.
The RDA of carbohydrates is generally placed between 45 and 65 percent of total daily caloric intake. Carbohydrates have always been consumed by human populations, and the nutrient has become especially important since the agricultural revolution around 10,000 BC.
In the mid 1800s, scientist Justus Von Leibig discovered the compound we call carbohydrate today.

Carbohydrates Deficiency

A deficiency of carbohydrates can be caused by an illness within the body consuming too much of the carbohydrates eaten or preventing the carbohydrates from being processed. In the case of cancer, fast-growing tumors thrive on the ready energy of carbohydrates and can drive available blood glucose down.

Diabetes can prevent the body from using carbohydrates through either insulin resistance or insufficient insulin production. Type 2 diabetes involves insulin resistance, in which cells no longer respond to insulin's signals to take up glucose. Type 1 and 1 1/2 diabetes can involve insufficient or totally absent production of insulin.

Carbohydrates Excess

Excess carbohydrates within the body can paradoxically also be caused by cancer and diabetes. While those disorders can keep the body from using the carbohydrates eaten, they can also cause levels of carbohydrate, in the form of glucose, to rise in the blood stream. In diabetes, lack of insulin results in low disposal of carbohydrates, causing blood sugar levels to stay abnormally high.

Cancer can eventually cause high blood glucose levels by depleting carbohydrates stored as glycogen. As glycogen stores stay low, insulin production decreases and fails to be enough for disposal of carbohydrates eaten at normal meals.