Cats can eat small amounts of plain bananas safely, but they should not eat banana bread. Banana bread contains high sugar, butter, and potentially harmful ingredients like raisins, chocolate, or artificial sweeteners that can be toxic or harmful to cats. Since cats are obligate carnivores, their diet should mostly consist of animal-based proteins, and banana bread offers little to no nutritional benefit while posing health risks due to added sugars, salts, and other ingredients. Therefore, it is best to avoid feeding banana bread to cats and stick to cat-appropriate treats and foods instead.