An elevated fasting or 2 hour post eating insulin level would contribute to the diagnosis. The ideal fasting blood sugar is between 80-100. Anything over that would raise suspicion. Often those with Syndrome X also have a low serum DHEA Sulfate level. The treatment is fourfold.
Exercise also uses up excess glucose, thus lowering insulin levels.
Change to a higher protein, higher soy diet. Use non starchy vegetables. If this has whetted your appetite for more information on Syndrome X, I refer you to a very useful book to be released next month. I will list them in the order of preference I would use in my practice. You can read the details by clicking on what interests you.