The absolute best dietary advise is to restrict carbohydrates to 30 grams or less per day for each and every day. Replace carbohydrate use by increasing fat consumption largely and moderating protein.
Follow this up with daily regular exercise such as non-stressfull exercise like walking, biking, cleaning the home etc.
I eat a 70% fat; 25% protein, and 5% or less diet. I've been doing this 12+ weeks now and eliminated all my insulin and oral diabetes medications. I've eliminated over 500 insulin injections in these 12 weeks alone.
Carbohydrates & sugars are the primary devil with respect to diabetes. To control this ideas via diet you need to reduce blood sugar levels and insulin levels simultaneously. This is best achieved by adopting a high fat low carbohydrate eating lifestyle.