Have you noticed your bowel movements looking a bit slimmer or lighter than usual?
“Pencil-thin” stool is something many people wonder about, and the reassuring news is that it’s often normal and short-lived.
Still, sometimes it can be your gut’s way of signaling that something needs a little attention. Read on to learn what might be behind these changes.
What Is Skinny Poop?

Skinny poop typically appears narrow, thin, or string-like, compared to your usual stool shape. A single episode is usually harmless. Recurrent skinny stool may be influenced by diet, hydration, gut motility, or bowel habits.
Why Does Skinny Poop Happen?
You’re Not Getting Enough Fiber (Surprised?)
Fiber helps give stool its bulk and softness. Without enough of it, stool can become small, dry, or thin. Fiber increases the volume of your bowel movements.
Dehydration
Your colon absorbs water to form stool. When you don’t drink enough, stool can become dry, compact, or narrow. We say it all the time and we’ll say it again: drink more water!
Stress or Changes in Routine
Stress can speed up or slow down gut motility, which can cause stools to look smaller or thinner. We have a deep dive on the connection between the gut and brain here.
Low Stool Volume (Small Meals or Grazing)
If you’re eating lighter than usual, or mostly low-residue foods, stool size can drop (and sometimes get thinner).
When Should I Worry About Skinny Poop?
If it happens occasionally and isn’t part of your normal pattern, it’s likely fine. However, if it occurs along with other symptoms such as bleeding, unexplained weight loss, severe abdominal pain, or if it lasts several weeks, there may be a deeper issue.
As always, if there is any question see a medical professional.
The Bottom Line
Skinny poop is often your gut’s way of saying, “Hey, can we get a little fiber and water down here?” Most causes are simple and fixable. Pay attention, support your gut, and always check in with a professional if something doesn’t feel right.
Bonny can help boost your stool's bulk with Fiber Bites in Cocoa and Very Berry and prebiotic fiber powders in Mixed Ripe Berries and Super Strawberry.
As always, we wish you pleasant poops!
Sources: Cleveland Clinic, Mayo Clinic, and Medical News Today