Bananas are sometimes recommended by doctors for people who have diarrhea, and are also recommended to be eliminated from the diets of those who are constipated. This leads people to the natural conclusion that bananas must have something in them that slows bowel movements. But is this true? Do bananas cause constipation?
Yes, at least some of the time. Bananas certainly can cause constipation in some people, although it largely depends on how many bananas you are eating, and how ripe they are.
Unripened (green) bananas are harder to digest, and therefore can lead to mild constipation. However, there are other reasons that bananas slow the bowels.
Bananas naturally contain something called pectin, which is a known binding agent. Pectin absorbs water within the bowels, leading to harder stools which are more difficult to pass.
Bananas also contain lots of starch, another contributing factor to constipation.
On the other hand, ripe bananas contain lots of fiber, which actually alleviates constipation! In this sense, bananas serve a dual role in controlling bowel movements. Small amount of ripe bananas will increase bowel movements, and larger amount of less ripened bananas will slow down your bowel movements and bind you up.