One thing I can say in defense of a plant based diet is that my blood pressure went down to normal when I was on a vegan diet and then it went back up when I began eating animal protein again. The problem for me on a vegan diet is that I am constantly hungry, I get light headed, and I can't lose an ounce of weight no matter how strictly I follow their plan for weight loss.

John, have you read Dr. Neal Barnard's Program for Reversing Diabetes? It might give you some insights on how to fight your diabetes on a vegetarian diet. Also, as HiDelight said, The Schwartzbein Principle has a chapter on how to eat low carb on a vegetarian diet. She is an endocrinologist from Southern CA and has helped many former vegetarians overcome their diabetes on a low carb diet.

Doctors have many differing opinions about what is the best diet for diabetics. The hard part is deciding which one to follow.