No, bananas are not toxic to cats. However, they should not be a staple in your cat's diet as they are not a source of nutrients that are essential for cats. Cats are obligate carnivores, which means that their bodies are designed to digest and use only animal-based proteins and fats. While bananas do contain some vitamins and minerals that can be beneficial for cats in small amounts, they are primarily composed of carbohydrates which is an energy source that cats cannot utilize efficiently. Too much banana in your cat's diet can lead to weight gain and other health problems associated with poor nutrition.