Perhaps the strongest association between weight gain, metabolic abnormalities, and disease risk is found with type 2 diabetes. (Type 1 diabetes typically affects younger people and is caused by the pancreas not producing insulin.) A majority of people who have type 2 diabetes are also overweight, and the incidence of type 2 diabetes is increasing as the population becomes more overweight.
About 90% of people with diabetes have type 2 diabetes, which develops when the insulin-producing pancreas cannot keep up with the body’s need for insulin, a hormone that helps blood sugar enter cells. With weight gain, cells in the body do not respond properly to insulin, causing an unhealthy rise in blood sugar levels. This is known as insulin resistance.The pancreas produces insulin, but the insulin no longer works effectively.
Weight gain dramatically increases diabetes risk. The risk goes up with weight increases after age 18. The risk also increases about 25% for every unit increase in BMI over 22. One study estimated that more than one-quarter of new cases of type 2 diabetes could be attributed to a weight gain of 11 pounds or more.
If we eliminate adult weight gain and obesity, we could eliminate over 80% of all type 2 diabetes. It is not surprising that one of the first treatment recommendations for type 2 diabetes is to lose weight.

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