I feel that Ketosis wouls actually increase insulin sensativity!
Ketosis is induced by lack of carbs, If you are keeping carbs low and not eating too much protein at one sitting your insulin levels as a whole will be lower than on a high carb diet.
Insulin resistance is from the body creating insulin to reduce blood sugar. I am no doctor but my understanding is if you eat high carbs all the time the body is producing insulin to remove high blood sugars. Constant pounding insulin and the cells becone resisant to the effects of the insulin. I feel if you drop the amount of insulin in your body your cells will slowly become more receptive to the insulin.
I bet you thunder could let us know a bit more on the subject.

Jag