If you cannot fast, eating a very small amount of a balanced low carb diet, will suffice.
People do not realise they really don't need much food to survive. It is the body demanding more useless carbs that most diabetics struggle with.
A small salad, with a piece of meat of your choice or some homemade soup.
There are plenty of ideas in the low carb forum.
I have come to realise that my body doesn't need a lot of food, and sometimes I think that my body works better without food, but I'm weird!
Always consult with your GP, or like me, I discuss everything with my endocrinologist.
Best wishes.