What is the function of insulin in diabetics ? and its relationship with fatty change ?

Insulin is just a natural enzyme. The body isn't making enough and so the body requires the insulin shot to help preforms natural duties. Now, to fatty change? If you mean in relationship with weight gain, well you could become diabetic. If you take in too many sugary foods, your body won't have enough to keep up. Sooner or later what you do have of your own natural insulin it will break down and become inactive. But if you are eating healthy and still gaining weight, then you should be fine. In the end, contact your doctor if you are nervous about it.