The show, Portlandia, spoofs the banana diet and likely the famous YouTube banana girl – see video below. The main character in the spoof becomes bloated and constipated. Based on my experiences, the opposite is the case, in that bananas increase the frequency of bowel movements. All fruit does this, since the trees or plants want us to spread their seeds.
Generally, I prefer to eat a mix of bananas, dates, oranges and what is in season. I did relate to the chore of bringing bananas to work.