hi there,
I searched all over to find information that could be helpful for you, and come up empty
.. A few message boards at diabetes and insulin pump sites had little to offer as well. All the "experts" could recommend was consulting a nutritionist. I did see several suggestions to have the thyroid function checked, since hypERthyroid can bring about weight and fat loss.
You didn't really say if you've always been thin, or how long you've been diabetic or how long you've been on the pump. The type of insulin may or may not make a difference as well. Insulin itself will lead to weight gain and fat storage for most people, so it may be just a matter of time for you, if you're fairly new.
Working out and building up lean muscle is a good idea, but isn't quite what you need, which is a layer of subcutaneous FAT in which to place the needle for the insulin pump.
Carbohydrates, especially refined carbs, white flour, white rice etc .. is more likely to become triglyceride fat rather than body fat. This isn't a good thing
. Depending on the carb level your doctor has prescribed, and your insulin dosing .. you're definitely better off choosing vegetables, low-glycemic fruits, whole grains and beans. FAT will be your best friend, I believe. FAT is neutral and has no effect on blood sugar or insulin. Choose olive oil, real butter (NOT margarine poison!) and eat the skin with chicken, eat the fat with your steak. Protein you'll have to experiment with .... since it will affect your blood sugar.
Hope there's something helpful for you,
Doreen