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Constipation and Weight Gain: Link, Root Causes, and Misconceptions

8 min read
a woman is holding her belly, feeling uncomfortable due to constipation_constipation weight gain
Melissa Mitri post Reviewer Melissa Mitri post Reviewer
Verified by Melissa Mitri
MS, Registered Dietitian, Former President of CT Academy of Nutrition & Dietetics

Table of Contents

If you are struggling to lose weight or worried about gaining even a little weight, you may wonder how much extra weight you have when constipated.

In this article, we explore the relationship between weight gain and constipation to examine if constipation can cause weight gain and bloating. 

Read on for more information about how much extra weight constipation can add and more.

Weight Gain From Constipation: Where Does This Idea Come From?

It is easy to suspect a connection between weight gain and constipation because of the bloating and water retention that accompanies constipation. 

However, the link between gaining weight and not pooping is more complex.

Let’s begin by defining constipation. According to the National Institutes of Health (NIH), constipation is a side effect or symptom (rather than a disease or medical disorder) that involves one or a few of the following characteristics: 

  • Less than three bowel movements each week
  • Dry, hard, or lumpy stools
  • Stools that are painful or difficult to pass
  • Feeling that not all stool has passed during a bowel movement [1]

While these characteristics typically classify constipation, only you know what’s normal for you and when there are significant changes in your usual bowel habits. 

For example, you may usually have one bowel movement a day and then notice you begin to have a bowel movement every other day instead. Or maybe you experience more difficulty with passing stools, or the consistency of your stool changes during bowel movements.

Bloating May Be Confused With a Rapid Weight Gain

Bloating is a common symptom that accompanies constipation, which causes many to believe they have rapidly gained weight from constipation. However, bloating is caused by trapped gas, which leads to abdominal pressure and a feeling of fullness. [2]

Bloating is not the same thing as actual weight gain in the form of fat, even if the scale shows a few extra pounds when you are constipated.

In other words, constipation does not cause belly fat to form, which would cause true weight gain. 

Conversely, when constipation resolves, the bloating, abdominal distention, and water retention will likely decrease, which can also cause weight fluctuation. This doesn’t necessarily mean that you have lost fat; it may just be normal weight fluctuations that often accompany constipation.

How Much Extra Weight Do You Bear When Constipated?

Have you ever wondered exactly how much weight constipation can add to the scale? 

According to Encyclopedia Brittanica, a person excretes about 100 to 250 grams or three to eight ounces of stool each day on average. [3] Additionally, excretion usually occurs one or two times each day. 

Therefore, if you were to have two bowel movements a day with 250 grams of stool per bowel movement, you could be holding up to 16 ounces of stool each day. Sixteen ounces is equivalent to one pound in weight. 

However, as mentioned above, your bowel habits may vary according to your normal routine. 

So, Can Constipation Make You Gain Weight?

In summary, constipation can make you gain a bit of weight, but it is short-lived.

It is not the same as gaining weight from fat because the weight fluctuations from constipation will likely resolve after the constipation is relieved. 

You may be a few pounds higher on the scale, but the extra stool in your body has mass and therefore carries weight. However, this is different from gaining fat because the weight will go down once the stool is passed.

Does It Mean Stool Softeners Do Not Work For Weight Loss?

Stool softeners, including prescription or over-the-counter laxatives, are solely intended for relieving constipation. Therefore, using laxatives for other purposes, including weight loss, is unsafe.

In fact, using laxatives for weight loss is considered laxative abuse. 

If you are unsure whether to use a laxative or stool softener, reach out to a medical professional for guidance. 

Can Constipation Make You Look Fat?

While constipation does not significantly influence how your body looks, you may notice slight abdominal distention that normally accompanies bloating and constipation. 

Common Causes for Constipation and Weight Gain

If you are experiencing constipation and weight gain, you may believe one causes the other. 

However, there are many possible causes that can lead to both weight gain and constipation. Let’s talk about some of the leading causes.

Poor Diet

If you have a diet low in fiber-rich foods, such as fruits, vegetables, and whole grains, you may have an increased prevalence of constipation. 

Fiber, whether soluble or insoluble fiber, is the part of a plant that the human body cannot digest. Therefore, fiber moves along the gastrointestinal tract and helps promote healthy bowel movements. Additionally, fiber-rich foods are more filling and satisfying, often helping to prevent overeating.

A poor diet can also lead to weight gain, as you are likely eating less nutritious, filling, and satiating foods, which encourage overeating.

Lack of Physical Activity

Another intersection between constipation and weight gain (or the inability to lose weight) is a lack of physical activity. Staying active helps move stool through the gastrointestinal tract and promotes healthy bowel movements. 

Additionally, a sedentary lifestyle that is lacking in physical can lead to weight gain.

Certain Medications

All medications have potential side effects that can include weight changes or constipation. 

For example, according to the Centers for Disease Control and Prevention (CDC), prescription opioids (such as morphine used to control pain) can contribute to symptoms of constipation. [4]

Therefore, your medication can be a cause of gastrointestinal symptoms of constipation and also weight changes. Always speak with your physician if you are experiencing persistent side effects from a medication.


The American Thyroid Association defines hypothyroidism as an under-active thyroid gland, which can result in constipation, amongst many other symptoms. [5] This is due to the body’s processes slowing down when thyroid hormone levels are depleted. 

Additionally, according to the NIH, hypothyroidism can also directly contribute to weight gain. [6]

Treat Constipation and Use Proven Weight Loss Strategies

If you are experiencing constipation, here are some of the best ways to relieve it:

  • Increase dietary fiber intake (such as in fruits, vegetables, and whole grains)
  • Exercise and stay active
  • Drink more water and other fluids

Coincidentally, these methods also help support healthy weight loss or weight maintenance. 

For healthy weight loss, incorporate more fresh fruits, vegetables, and whole grains into your diet to support fullness and satiety. 

Focusing on the foods you would like to add to your diet (rather than emphasizing everything you want to take away) will often lead to a more successful and sustainable lifestyle change as opposed to a fad diet. 

Managing your weight on your own may be challenging. Speaking with a registered dietitian nutritionist will allow you to discuss your weight loss and health goals to get individualized feedback, advice, and recommendations.

A registered dietitian nutritionist can help you lose weight in a healthy and sustainable way. 

Additionally, if you are struggling to lose weight, you can use an all-in-one weight loss app that can help you monitor your progress toward your goals, track workouts and meals.

However, it is essential to note that if a disease or medical condition is contributing to your weight gain or constipation, address your concerns with your physician or specialist. 

Wrapping Up

Let’s summarize some key takeaways about the relationship between constipation and weight gain. 

  • The NIH defines constipation as experiencing less than three bowel movements each week, dry or hard stools that are difficult to pass or painful, and feeling that not all stool has passed.
  • It is normal to experience bloating and abdominal distention when you are constipated.
  • The bloating and constipation can cause slight weight fluctuations. However, this weight gain is likely not due to actual fat gain but instead is related to trapped gas and pressure in the abdomen.
  • Typically, when the constipation is resolved, your weight will go back to your usual. A normal bowel movement is up to half a pound up to twice each day. Therefore, if you are constipated, you may be holding on to up to a pound of stool each day. 
  • Do not use laxatives for weight loss, as this is considered laxative abuse and unsafe.
  • There are many potential causes for both constipation and weight gain, including poor dietary habits, lack of exercise, certain medications, and hypothyroidism.
  • Increasing physical activity, improving your diet, and increasing your water intake can aid in relieving constipation and promoting weight loss or weight maintenance.
  • Speak with a registered dietitian nutritionist for individualized nutrition recommendations to lessen and prevent constipation. 
Disclaimer This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!

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