I've been diagnosed, and also had a glucose tolerance test that confirmed the insulin resistance aspect.
I'm on metformin, and my doctor recommended a low carb diet, but warned me not to go too low. When I asked him what too low was, he admitted that he didn't know.
I've learned that most doctors get very little nutritional training in medical school. So, I've done a lot of reading on insulin resistance and Metabolic Syndrome, also known as Syndrome X.
I'm still having trouble restricting carbs as much as I should. Tonight hubby made a baked rice dish, and I ate too much of it. I didn't do badly calorie-wise, but when I eat foods that high in carbohydrates I have to be extremely serving conscious, because while I'll lose weight consistently on 1800 calories of low-carb, I often won't lose weight on 1800 or even 1500 calories of high carb. It doesn't make sense, even to me, which is why I think I'm so prone to testing and retesting the theory.
I recommend a food journal, because it will help you see patterns, you will actually see in black and white whether or not you lose better when you restrict carbs (and how much better). Calories count, but with Metabolic Syndrome, sometimes carbs count more.
I suspect that the body is more efficient at using carbohydrates as fuel than at using fat and protein. I think more calories are "wasted" when eating low-carb. It's just a theory of course, there are other possible reasons. For example, when I'm eating low-carb, it seems that my body temperature is slightly higher, this would make some sense as a lower body temperature requires fewer calories to maintain than a higher one.
You do have to be careful not to reduce fats or carbohydrates too far. You need a little fat in your diet, especially if you're restricting carbohydrates too far. My personal belief is that the "Atkins flu" can be a sign that you're reducing carbs too far, rather than a result of "carb withdrawal" in the sense it is usually described - but that's a personal opinion.
For me a high-protein, low carb exchange plan is my ideal plan. It works the best. Even though I tend to follow it rather sloppily at times (but that's my problem not the plan's).
I slightly modified a plan I found on the hillbilly housewife site:
http://healthy.hillbillyhousewife.com/foodplans.htm