The books below have good, research-based information and I use them with my clients all the time with great results. Pink links will take you directly to listing and description on Amazon, which helps me keep this website free for you.
Easy to understand, very solid scientifically, walks you through understanding the underlying problems with diabetes and then gives you specific strategies to prevent and reverse pre-diabetes and diabetes the natural way. Comes highly recommended by Dr. McDougall and other physicians in the Lifestyle Medicine space.
Includes a whole chapter on the science behind nutritional intervention and their specific effects on diabetes and blood sugar. This is also available as an audiobook.