http://www.amazon.com/Motivational-Interviewing-Nutrition-Fitness-Applications/dp/1462524192
I actually haven't read it yet, but I took a semester class with her and attended a webinar that she did as well. I found the class and webinar to be helpful and I've been meaning to read the book. It also has some Health at Every Size stuff in there as well, so you might not like it if you aren't into that.