If you've ever had a bowel movement and felt lighter afterwards, you might wonder: Do you lose weight when you poop?
Here, Niket Sonpal, MD, a New York-based internist and gastroenterologist, answers that question and discusses four big bowel changes you might see during your weight-loss journey.
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What Does a Healthy Bowel Movement Look Like?
First things first, “everyone's bowel movements are different, but a healthy one almost looks like the shape of the colon, is soft and does not cause pain upon exit,” Dr. Sonpal says. For reference, check out the Bristol Stool Chart.
How Much Does Poop Weigh?
Here's an interesting poop fact: Your poop can vary in weight depending on what you eat, your water intake and your body size. Eating high-fiber foods, for example, increases the weight and size of your poop, per the Mayo Clinic.
One September 2015 review in Critical Reviews in Environmental Science and Technology found that healthy adults produce an average of 128 grams (about a quarter pound) of feces per day, but this can range from about 51 to 796 grams (0.1 to 1.75 pounds), based on the individuals studied.
The review also says that the more you poop, the less each bowel movement will weigh.
Do You Lose Weight When You Poop?
You may lose a bit of weight each time you poop, but this is typically just the weight of the poop itself. As noted above, the average bowel movement weighs somewhere around a quarter of a pound, so pooping isn't likely to lead to any noticeable weight loss.
Keep in mind that poop is about 75 percent water, and the other 25 percent is a mix of dead bacteria, indigestible food, cholesterol and other inorganic substances, according to the 2015 review in Critical Reviews in Environmental Science and Technology. So, no, you don't lose fat when you poop, and pooping does not help you lose weight. (If you're wondering about "fatty stools," those happen when your body can't break down foods high in fat, per the Cleveland Clinic.)
Instead, body fat is "burned" when you take in fewer calories than you expend, and fat leaves your body through your sweat, urine and breath, per the Cleveland Clinic.
You burn calories when you poop, just as any bodily movement or function burns calories (read: breathing, eating, etc). There are no good estimates for how many calories pooping burns, but it's likely to be fairly minimal.
What about the flip side: Can constipation cause weight gain? Poop weight varies, as we noted above, so it's possible to see the scale tick up slightly if your bowels are backed up. However, this change is in the realm of normal weight fluctuations and doesn't lead to long-term weight gain. Rather, constipation and weight gain are linked because the common culprits that can lead to constipation — poor diet, poor hydration and lack of exercise — can also lead to weight gain.
4 Ways Your Poop Might Change When You're Losing Weight
1. You Might Poop More Often
Visiting the porcelain throne more often? That's likely due to healthy dietary changes on your weight-loss plan. If you're noshing on more fruits and veggies, you'll reap the benefits of pooping every day.
"Eating more plant-based foods will increase the amount of soluble fiber in the stool," which will become fluffy, softer and easier to pass, Dr. Sonpal says. That's because fiber "causes more distention of the rectum, making you go to the bathroom more frequently," he explains.
More regular poops can also occur if you're working out more.
"Exercise makes everything in your abdomen compress," Dr. Sonpal says. In other words, "your abdominal muscles are literally promoting you to poop."
Just make sure it's not too frequent — i.e., if you're waking up to poop, you may have underlying bowel conditions.
2. You May Experience Constipation
Is trying to poop as strenuous as your daily cardio session?
If you're trying to build muscle or stay satiated at meals, you might be introducing more lean proteins into your daily menu. But eating too much of this mighty macro may bind your bum.
Dense proteins — which take longer to digest — can lead to less frequent bathroom trips and constipation, Dr. Sonpal says. The result: Your stools may become hard, chunky and feel uncomfortable on the way out.
Cutting carbs from your diet — often a go-to weight-loss strategy — can cause constipation too. That's because when you slash too many carbs, you also eliminate a lot of essential fiber sources, such as whole grains, fruits and legumes, which keep your poop schedule on track and running smoothly.
To combat these constipating effects, be sure to balance your diet by drinking plenty of water and filling your plate with fibrous foods, Dr. Sonpal says.
If you're following a carb-restricted diet like the keto or paleo diet, you can still reach your daily fiber quota by sticking to non-starchy vegetables (like leafy greens, carrots and squash) and low-carb fruits like avocado and raspberries. Adults should aim to get about 25 to 38 grams of fiber per day, according to Harvard Health Publishing.
3. You Might Get Diarrhea
Alternatively, low-carb eating plans can also produce runny, bad-smelling poops. Take the keto diet for example. Because sugar is a major no-no on this diet program, many keto devotees may consume foods containing low-carb artificial sweeteners and sugar alcohols. These sugary alternatives, which are difficult to digest, can have a laxative effect leading to liquidy poops, according to Harvard Health Publishing.
What's more, keto requires you to eat a lot of fat. But consuming too many fatty foods can disrupt digestion and result in the runs as well. This can be a double digestive whammy if you're chomping on more cheese and you have a lactose intolerance (about 30 to 50 million Americans do, according to Boston Children's Hospital).
Does Diarrhea Cause Weight Loss?
Diarrhea, whether acute or chronic from a condition like irritable bowel disease, can cause weight loss. This weight loss can be due to a loss of water, leading to dehydration, or from nutrient deficiencies due to malabsorption, per the Mayo Clinic. If you notice a change in your weight associated with diarrhea, talk to your doctor.
4. Your Poop Color May Change
Does the shade of your stool seem different lately? That's because your poop's pigment is impacted by what's on your plate, according to the Cleveland Clinic. So, if you're eating a rainbow of fruits and veggies, expect your feces to reflect that.
For example, dark, leafy greens can generate bright green poop while beets and cherries may turn your stool reddish. Meanwhile, blueberries can taint your toilet waste a deep blue (or even black) and carrots can cause orange-hued poop.
But if the poop color changes persist, or you can't connect them to anything you ate, it might be cause for concern, per the Cleveland Clinic. Red or black poop may indicate blood in the stool, while gray stool could signal an issue in the pancreas or bile ducts.
In these cases, contact a medical professional who can help you identify any serious problems.
- Harvard Health Publishing: “Is something in your diet causing diarrhea?”
- Cleveland Clinic: “How Your Diet Can Affect Your Poop Color.”
- Harvard Health Publishing: “Should I be eating more fiber?”
- U.S. National Library of Medicine: "Lactose intolerance"
- Mayo Clinic: "Diarrhea - Symptoms and Causes"
- Mayo Clinic: "Dietary Fiber: Essential for a healthy diet"
- Cleveland Clinic: "Where Does Body Fat Go When You Lose Weight?"
- Cleveland Clinic: "Steatorrhea (Fatty stool)"
- Boston Children's Hospital: "Lactose Intolerance"
- Critical Reviews in Environmental Science and Technology: "The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology"