Diabetes can come in one of two forms: Type I and Type II, both of which have similar symptoms but very different causes. Type I diabetes is a disease whereby the body's own immune system attacks and kills the cells in the pancreas which produce insulin, leaving a person's body without insulin, and unable to regulate its blood sugar levels. Type II diabetes is a disease which results when the body's cells become resistant to insulin. In Type II diabetes, unlike in Type I, insulin is still produced by the body; it just isn't used correctly. Both diseases result in abnormally high blood sugar levels (hyperglycemia), which can cause kidney, eye, heart, blood vessel, and other diseases.

Symptoms of diabetes include lethargy, extreme thirst and urination, extreme hunger accompanied by rapid loss of weight, and blurry vision. These are all results of the body's inability to transport sugar (energy) from the bloodstream to the body cells. While it was previously assumed that having diabetes was a clear-cut ticket to further disease and complications, it has been shown that good control (keeping blood sugars close to a non-diabetic person's) can be attained through combinations of insulin therapy, diet, exercise, and other medications... and that keeping in good control will help prevent or reverse other diabetic complications.