How Do Bowel Movements Work — and What's Normal?

A woman sitting on the toilet with toilet paper in her hands

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A bowel movement, or BM for short, is when your body moves waste leftover from digested food through your intestines and out your anus. This process is also known as pooping or defecation. 

After you eat or drink, your digestive system breaks down food and absorbs nutrients. The BM process starts in your small bowel (aka small intestine), where anything left after digestion moves to your colon (aka large intestine). There, undigested food, mucus, intestinal lining cells, and bacteria form into solid waste and move to your rectum, the tube between your colon an anus. Your bowel muscles then help you push out any stool through your anus. Voila! You just had a bowel movement. 

Still curious about BMs? Are your bowel movements healthy? Let’s look at everything we know about bowel movements and why you might be irregular.

What is a Normal Bowel Movement?

What is considered a “normal” BM depends on things like poop consistency, poop color, and frequency. This can vary per person, but typically a normal bowel movement fits into these parameters:

  • You poop one to three times a day or three times a week
  • Your poop has a soft to firm texture
  • Your poop is a medium to dark brown color
  • Your BMs are painless

The Bristol Stool Chart also shows how stool shape and consistency are related to regular BMs. The “normal” poop zone on this chart includes:

  • Type 3: Sausage-esque stool with cracks on the surface.
  • Type 4: Smooth, soft stool that resembles a snake (FYI: the most healthy form of poop).

What Factors Can Impact Your Bowel Movements?

It's common for your BMs to get off their regular schedule from time to time. Things you eat and drink can affect the look and frequency of your bowel movements. Changes in your routine and health can also make you irregular. 

Things that can affect your BMs include: 

  • Eating red or green foods: Foods like spinach can cause green poop while eating beets can make your stool look red. 
  • Dehydration: Drinking too little water can make stool hard to pass. Alcohol overuse can also dehydrate you and make it difficult to poop.
  • Fiber Intake: Eating fibrous foods helps add bulk to stool and move digestion along, making it easier to pass. Consuming too little fiber can lead to infrequent BMs and hard stool. 
  • Being sick: Infection can target your bowels and cause loose, watery BMs. Being ill may also make it hard to digest carbs like lactose or proteins in milk products. 
  • Food allergies or intolerances: Eating foods you’re allergic or intolerant to (like dairy or gluten) can lead to loose stool and urgent BMs.
  • Medications: Long-term antibiotic use can cause loose, urgent BMs. Some medicines can make BMs infrequent, difficult to pass, or watery.
  • Stress: Stress can affect the muscles of your digestive system, resulting in urgent or infrequent BMs.
  • Traveling: Sitting for long periods in planes and cars, changing your eating and drinking habits, or picking up a bug can lead to travelers’ diarrhea or constipation. 
  • Pregnancy: Hormonal changes during pregnancy can slow down digestion and make it hard to poop. 
  • Inactivity: Not moving your body enough can slow down your bowels and make constipation more likely. 
  • Gastrointestinal disorders: Irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD) can back you up or make BMs watery and loose.

What are the Signs of Bowel Problems?

An unhealthy bowel movement typically means pooping too little or too much. Your stool may also be watery or extremely hard. These bowel problems are all related to constipation or diarrhea. When you're constipated, bowel movements typically happen less than three times a week, and waste moves too slowly through your bowels. Diarrhea, on the other hand, is associated with urgent, loose or watery BMs when waste moves too quickly through your bowels.

Signs of bowel problems related to constipation include:

  • Having less than 3 BMs a week
  • Lumpy, log-shaped stool
  • Small, hard pellets of poop
  • Painful BMs
  • Feeling like you still need to poop

Signs of bowel problems related to diarrhea include:

  • Watery, loose stool
  • Mushy poop with sharp edges
  • Small, soft blobs of poop
  • Abdominal pain and cramping
  • Urgent and frequent BMs

Unhealthy bowel movements may also be associated with strange poop colors, like:

  • Black, tarry: Upper intestinal bleeding (some medications can also alter color).
  • Green: Lack of bilirubin makes poop brown when stool passes too fast. 
  • White or pale: Blocked bile duct related to liver or gallbladder issues.
  • Red: Bleeding related to hemorrhoids, constipation, or lower GI tract bleeding.
  • Yellow, greasy: Not absorbing nutrients, and poop has too much fat content (often associated with celiac disease).

When to See A Healthcare Provider

Talk with your healthcare provider if your BMs are affecting your quality of life due to chronic constipation or diarrhea. Bowel movement problems can indicate an underlying health condition like depression, cancer, IBS, IBD, or thyroid issues. 

Call your healthcare provider if you experience these signs linked to irregular BMs:

  • Loose, watery stool for more than two days (24 hours for children) 
  • Fever 
  • Vomiting
  • Unintentional weight loss
  • Six or more BMs in 24 hours
  • Black, tarry poop (possible medical emergency related to internal bleeding) 
  • Blood in poop
  • Abdominal or lower back pain

Your provider may also determine that your irregular BMs are due to diet or lifestyle changes. Different methods your provider may recommend to help your bowels move along include: 

  • Eating more fibrous foods
  • Drinking more Water
  • Getting regular exercise
  • Bowel training (trying to poop at the same times)
  • Changing medicines and dietary supplements
  • Taking a laxative
  • Taking medications to reduce constipation

A Quick Review

A bowel movement is basically a more scientific way of saying pooping. During a BM, your body moves waste after digestion through your small and large intestines. This waste is stored in your rectum before you poop. Regular bowel movements usually happen one to three times a day or three times a week. 

Diarrhea is a sign that your BMs are happening too fast, while constipation shows BMs are too slow. Irregular bowel movements can signify a health condition or a change in your diet or lifestyle. Talk with your healthcare provider if your BMs are uncomfortable and affecting your life. They can help you determine if an underlying condition is to blame or if you need to eat more fiber. 

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