What happens if a diabetic person eats banana......

Diabetes & Sugar: Bananas, while a good source of potassium, are 100% carbohydrate or sugar calories. If your diet is balanced and you are counting your sugars carefully then if the banana fits into that then fine. But, in general fruits are mostly if not alway all carbs.

They get healthier..: Diabetic should eat fruit, vegatable, and lean protein primarily. They should avoid starches, processed food and junk food.