Excess fruit intake has the potential to cause diarrhea. Normal bowel habits are all based on what nourished your body at least three hours ago. Fruits have sugars that bacteria love to eat, which produce natural laxatives in abundance – basically, fruit provides fertile grounds for lots of “friendly” flora. And here’s the catch-22. When you’re sick and eating nothing but fruits, you wash down those kinds of stomach-friendly bacteria with every glass of water and Gatorade that enters via IV drip. Colon good guys can’t help because there isn’t even a dirt road to cling onto and they just starve away.