It is better to refrain from eating them if you are diabetic.
Diabetes.co.uk. named fruits that are contraindicated for diabetics. They include bananas and oranges.
These fruits contain a lot of natural sugars. Therefore, they should be eaten with caution.
That said, the UK Department of Health recommends that healthy people eat up to five servings of fruit a day. You should replace sweet desserts with it.
Earlier the specialists of Beijing University of Aeronautics and Astronautics named bananas as radioactive fruit because of the potassium-40 content, which gives weak ionizing radiation. However, it is negligible. One person would need to eat 35 million bananas to get a lethal dose of radiation.