In order to appreciate the cause for the condition known as diabetes, one must first look at what occurs in the body of a healthy individual, particularly after such an individual has recently eaten a food that is high in carbohydrates (sugar or starch). Digestive juices rapidly act on a starch, changing it to a simple sugar. All sugars in digested food mix with all the foods in the stomach. That mix in the stomach then enters the intestines.

The nutrients in the fluid of the intestine must reach the cells of the body. The intestinal wall allows passage of sugar from the intestinal cavity into the bloodstream. That passage takes place in both a healthy individual and in an individual with diabetes.

Once the bloodstream has acquired sugar from the intestines, then special endocrine cells in the pancreas get a signal. That signal tells those cells, located in the Islets of Langerhans, to release insulin (a chemical that acts on the body's cells). The specific pancreatic cells in a healthy individual respond quickly to the "call" for insulin. The Islets' cells in a diabetic do not give the proper response.

If a person has Type 1 Diabetes, then his or her pancreatic cells lack the ability to produce even a drop of insulin. If a person has Type 2 Diabetes, then his or her once well-functioning Islets' cells demonstrate a sharply diminished ability to make insulin. In either case, the body's cells do not receive the chemical message that facilitates the absorption of blood glucose by those same cells.

Because the cells of a diabetic lack the ability to absorb glucose from the blood, the cells of a diabetic become deprived of a needed energy source. Meanwhile, if the diabetic continues to ingest foods high in carbohydrates, then his or her bloodstream will become "flooded" with glucose. Eventually all of that glucose passes through the kidneys, and it leaves the body in the urine.

The physiological changes that take place in a diabetic patient produce certain tell-tale symptoms. The patient might complain about the need for frequent urination. The patient often speaks about having periods of great thirst. The patient experiences repeated periods of unusual and unexpected fatigue.

The above symptoms show up among individuals with both Type 1 and Type 2 Diabetes. A few symptoms are type-specific. For example, in Type 1 Diabetes the patient can experience a rapid weight loss. In Type 2 Diabetes, the patient frequently begins to store more fat, and at the same time that patient could well exhibit a growing desire for sweets and starches.

Type 1 Diabetes is an inherited condition. The treatment for Type 1 Diabetes is insulin. Until recently, that insulin had to come in the form of insulin injections. Newer medical techniques now allow patients to wear an insulin pump.

Health professionals struggle to reverse the alarming rise in the reported cases of Type 2 Diabetes. They encourage the eating of high-fiber foods and foods rich in complex carbohydrates. Such foods do not "flood" the bloodstream with glucose.