I'm still waiting for my copy of the book, so I hesitate to post, but both extremes of this argument drive me crazy. If being fat doesn't cause health problems, in my experience at the very least, it exacerbates health problems.
But, I am annoyed with doctors who blame everything on excess weight, and dismiss treatment options other than losing weight.
Sending me home to lose weight without doing further tests or providing treatment in the meantime, is often so frustrating. Being fat may have caused my respiratory infection, but I still may need an antibiotic. I had a large ball of fungus growing in my sinuses that went undiagnosed for years because every doctor I went to said my sinus problems were caused by my weight, and that they'd just disappear if I lost weight, so they wouldn't offer any treatment other than an allergy medication here and there.
If I hadn't found a doctor who was willing to help me WHILE I was trying to lose weight, I'd probably still have that fungus growing in my head.
There has to be a middle ground between ignoring the health risks of obesity, and blaming everything but the weather on excess weight.