Stop smoking. Aside from the well-documented lung cancer risks, smoking is of extra concern for diabetics. Diabetes and smoking both put you at an increased risk for heart disease, nerve damage, and kidney problems. Smoking also causes a rise in blood sugar. Either risk alone is enough for concern, but a diabetic who smokes is at a much higher risk of developing problems.
Another good way to prevent diabetes is to control your diet. Eating too many foods with a high glycemic index, which usually means foods with large amounts of simple sugars like candy or soda, can cause your cells to become less sensitive to insulin, which can cause diabetes. Eat less and save yourself the medical bills.