When you suddenly experience increased bowel movements it can be because of consuming more fiber than you normally would.
When you suddenly start increasing your intake of fiber then you begin to have more increased bowel movements which is normal.
The more fiber based foods you eat the more often and more you'll need to poop or have a bowel movement.
However if you have not increased your intake of fiber then you could be having the increased bowel movements as a result of medications such as antibiotics or metformin.
Also sugar intake and other fat intake can cause increased bowel movements.
Another common cause of increased bowel movements is irritable bowel syndrome.
So if you haven't increased your intake of fiber based foods or sugar intake etc and the increased bowel movements have occurred suddenly and continue longer than a few days then you should see a doctor because you could have irritable bowel syndrome or other bowel problems.