It is bad to eat raw green bananas because they can cause constipation and other digestive problems. Anything that is not sugar, such as a raw green banana must be converted it sugar first before use. Fruit ripening therefore is important as it acts as predigesting the food for you.
It is not bad to eat green bananas. Bananas are raw whether they are yellow or green, and will not do any harm in either color. In many Caribbean Islands, people intentionally eat bananas when they are green because they work better in cooking and when freezing or canning.
Foods high in fat content and sugar cause constipation, especially eggs and other dairy products, processed foods such as corn, bread, pasta, pizza and heavy sugar products like pastries, pies among others. A low-fiber diet and insufficient fluid intake largely contribute to constipation or slow bowel movements which can be painful sometimes.