Previous gestational diabetes increases the risk of type II diabetes in later years. Women who have given birth to babies weighing 9 pounds or more. I diabetes, type II diabetes also runs in families. This suggests that there is some type of genetic component. In fact, a genetic link seems even stronger in type II diabetes than in type I. Scientists have not yet put their finger on a single gene that causes the disease.
Researchers also suspect a genetic susceptibility to obesity.
Obesity is the single most important cause of type II diabetes. Definitions of obesity differ, but in general, you're obese if you weigh at least 20 percent more than what is recommended for your height and build. Three-quarters of type II diabetics are or have been overweight. For reasons that remain unclear, carrying excess body fat somehow causes insulin resistance. That's why type II diabetes is usually treated with diet and exercise.