Dieting with Obstacles - Can someone help me out....

My hubby was diagnosed as Prediabetic...he is thin and does not meet any of the profiles lol.....what is the best type of diet to put him on to help stabilize his blood sugars? He already has a gym membership with me that he NEVER uses so he will be doing that too lol....Thanks for any advice!

Google low gylcemic diet... or diabetic diet

South Beach stabilized my sugar elvels. My doctor is delighted.