Most people who came in with constipation were already eating a lot of fiber—so they weren’t lacking it, which challenges the idea that fiber deficiency causes constipation.

This study shows that people with constipation don’t need fiber to poop normally—many felt better when they stopped eating it.

Most people with chronic constipation chose to keep eating less fiber after trying it, because they felt better—only a few went back to eating lots of fiber.

People with constipation who kept taking fiber pills or eating lots of whole grains didn’t feel better—even if they tried to change their habits, the fiber kept them feeling the same.

People with constipation who ate no fiber stopped straining to poop, while everyone who kept eating fiber still had to strain hard.

Older people with constipation were a bit less likely to stop eating fiber, but it wasn’t a big or clear difference—age didn’t strongly predict who changed their diet.