Any weight loss will help, but do it sensibly so it sticks. Whether you follow whats in that book, use atkins, weight watchers, south beach or any other reasonable diet plan. Exercise reduces insulin dependence. The combination of regular exercise and even moderate weight loss makes a big difference.
GO for it.
Its ok to question Why? as long as it doesn't keep you from dealing with your issues. Has your doctor also prescribed meds, like metformin?
You CAN manage this and be healthy, maybe healthier than you have been in a while. GOod luck
zen and the art of weight loss, finding the true path of en-lighten-ment