Think Like a Pancreas is great (or Stink like a Pancreas as my 9-year old has christened it), it's my holiday reading this year and I'm finding it very helpful even just a month post diagnosis.
I've done a lot of research into sports nutrition myself, but this goes a whole lot deeper than the macro nutrient balance and energy pathways into the detail of the various hormonal systems.
I've got another good one waiting at home for me next week hopefully and a sports physiology book on my kindle. Time to put those novels away and get serious.