Research found that our body is design to squat over a toilet rather than sit on it.
As children, we instinctively crouched down when the time came to eliminate, which is why this position is still practiced by the majority of the world. From Korea to the Compton blocks, squatting is a natural resting position.
As well, it is used during childbirth. Gravity sets in and whoosh.
When placing your knees closer to your torso it causes less strain and time to defecate. The best way to achieve this natural position is by using a stool.