I haven't tried the Insulin Resistance diet book, but I've been following the Zone diet for about 18 years with excellent results. I reversed my insulin resistance (confirmed by my dr with fasting insulin blood tests), lost 100 pounds and have easily maintained the weight loss. My adult daughter who has PCOS has also successfully used (uses) the Zone diet together with Omega RX fish oil. It's amazing stuff.
Lost 100 pounds with the Zone 18 years ago and have kept it off!
You can see photos of my favorite meals and snacks here: