Those who find types 3 or 4 in the toilet bowl may also want to observe how quickly their feces sink in water. Ideally, they should not plummet straight to the bottom, as this would indicate the possibility that they still contain nutrients that have not been digested properly. Feces that sink slowly contain bubbles of gas that keep them afloat in water. These gas bubbles are produced by gut bacteria that mostly perform useful services.
