Could you tell me why insulin injection are not useful in controlling obesity related diabetes?

Insulin incr. weight: Insulin makes you gain weight. Insulin gets sugar in the cells which makes you gain weight... in lament terms. Therefore, although you are doing a great job at controlling your blood sugar, you need to still work with diet and exercise to decrease Insulin resistance and lose that belly fat and overall weight.

Insulin resistant.: Obese individuals get diabetes because the fat tissue in their bodies confers upon them resistance to insulin. So it's not a lack of insulin causing the problem, but a resistance to the effect of insulin.