Bananas are on the list of safe foods for guinea pigs to eat. Because bananas are high in sugar, they should only be occasional snacks, however.
Other foods guinea pigs can eat as snacks include bell peppers, apples, pears, cherry tomatoes, most types of berries and melons of all kinds. Guinea pigs should eat low-sugar vegetables and fruits on a daily basis, such as spinach, kale, romaine lettuce, cucumbers, carrots, celery and similar produce. Some guinea pigs are picky about their food and refuse to try new items, but persistence usually convinces them to add a new fruit or vegetable to their diet.