As Sid said, try it and monitor to see how it effects your body, but talk to your doctor as it may effect yuor medication.
I couldn't fast because of the dawn phenomenon, my BG just rises and keeps on rising until I eat something non- carbohydrate. Though I could eat breakfast and then nothing else for the rest of the day. Other people may find that their BG goes too low if they fast.
You are an individual and you are the expert in your body, try it carefully and see what effect it has.