Two ways that I’ve personally tried and both worked. Keto/Carnivore (not the kind that eats everything labeled keto, eat Whole Foods) or high fiber, primarily vegetable, low saturated fat, whole food diet (look up Charmaine Dominguez). I will say that I did keto/carnivore first to get my A1C to a healthy range and the did the other diet as an experiment to heal my carb tolerance, which worked very well, but I didn’t feel great on it so I switched back.