Constipation is the most common digestive complaint in adults. There are various causes of constipation including weight loss. In this article we will examine why weight loss causes constipation and the steps to resolve it.


What is Constipation?

Constipation is defined as difficult or uncomfortable bowel movements. There is no universal standard for “normal bowel movements” since they vary for everyone. However, two or less bowel movements a week is suboptimal. Bowel movements vary based on eating habits, activity level, medical conditions, medications, and stress.

According to the World Gastroenterology Organization if you meet any 2 of the following criteria for at least 12 weeks (within 1 year) you may be constipated:


  1. Less than 3 bowel movements a week
  2. Stool is hard or difficult to pass
  3. Small stools or feeling the bowel movement has not completely evacuated
  4. Straining to pass stool
  5. The need to digitally manipulate stool (using finger to remove)


But doesn’t obesity cause constipation?

Being sedentary contributes to constipation; however, obesity is more correlated with loose stools and diarrhea than constipation. Obesity is also associated with increased risks of gastroesophageal reflux disease (GERD) and other functional GI disorders such as Irritable Bowel Syndrome (IBS).


How does weight loss cause constipation?


Changes in diet and eating behavior

 Deviations from routine eating patterns, which often occur in weight loss, can cause constipation due to disruption of circadian rhythm. Circadian rhythm ensures that biological processes are completed according to proper timing and the digestive system, like the brain, has its own circadian rhythm. This explains why you may get hungry at the same time each day or have certain eating habits that are difficult to change no matter how hard you try. This is also the reason for constipation while traveling or on vacation, it is due to changes in eating pattern, meal frequency, food volume, meal timing, and overall eating behavior.


  • Less Food Intake In weight loss, people often eat less food and eat less frequently. Eating less food reduces the muscle contractions within the digestive tract therefore reducing stimulation of the bowels. This muscle movement is called peristalsis and it happens due to the normal rhythm of the bowels on a periodic basis but also happens as a result of food entry into the GI tract. As less food enters the mouth, stomach, and intestines, there is less need for muscle movement and this leads to less propulsion of stool; therefore, causing constipation.
  • Not enough water – Water is essential for digestion and is mainly absorbed in the large intestines where stool is formed. Adequate water intake helps to push fiber forward and softens stool.
  • Fiber- Dietary fiber is a double-edged sword. Constipation can occur due to a low dietary fiber intake or high fiber intake with inadequate water. Fiber is not digested by the body, so it is pushed through the digestive tract leading to the bulk of stools. Fiber also expands and absorbs water which helps with bowel movements.
  • Dietary impact on gut flora and microbiome- The gut flora are the natural bacteria that live in the intestines and help with breaking down food, releasing nutrients and other chemicals essential for digestion. These bacteria also aid in the production of vitamins and minerals like Vitamin K. It has been shown that obese individuals have lower variety of gut bacteria and therefore gut microbiome may have an impact on weight.

To increase microbiome, eat a variety of fruits, vegetables, fermented foods, nuts and seeds and grains. If needed prebiotics and probiotic supplements can also be used to aid in constipation.


  • Food Sensitivities – A food sensitivity or food intolerance occurs when the immune system (also referred to as leaky gut) responds to certain foods or food parts. The most common inflammatory responses to food sensitivities are GI related and range from reflux to loose stools, bloating and gas, to constipation and irritable bowel syndrome (IBS).

Could you have a Food Sensitivity?

Order a Home Food Sensitivity Kit

or call 704-997-9661 to schedule an in-office food sensitivity test

Read more about Food Sensitivities in the FAQ (find topic in drop down) Here


Physical activity reduces constipation


Muscle contraction and tone play an important role in digestion and stool formation. Physical activity increases muscle tone and reduces stool transit time via direct force especially with physical activities like walking, jumping, and running. In addition, being sedentary increase the risk of constipation.


Ways to increase dietary fiber


Foods high in Fiber:

The dietary forms of fiber come from fruit, vegetables (including beans and legumes) nuts, seeds, grains, and supplements. If you are in a weight loss program, you should choose dietary sources of fiber based on your personalized weight loss and nutrition plan.


Non starchy Vegetables high in fiber








Bell peppers

Green beans


Brussel sprouts

Green peas

Collard greens



Swiss chard








Starchy Vegetables high in fiber

White potato (higher with skin intact)

Sweet potato

Butternut squash

Sweet corn














Nuts and Seeds

Chia seeds








Whole wheat spaghetti



Oat bran

Brown rice




Fiber Supplements and Medications

Supplements can be natural or synthetic and are used to aid in stool production, bowel regulation, and more comfortable bowel movements for individuals with constipation.

  • Psyllium Husk –is a natural fiber supplement composed of both insoluble and soluble fiber that makes stools softer and easier to pass. Psyllium husk also increases bulk of stool aiding in the elimination of digested foods
  • Various fiber brands such as Citrucel, Metamucil, FiberCon, and Benefiber can be found at the local pharmacy. Some of these forms of fiber contain fillers, added sugars and artificial flavors so always read the ingredient list when choosing supplements.

Stool softeners

Docusate sodium or Dulcolax and Colace are stool “surfactants” that work by lowering the surface tension of stool making it easier to absorb both water and fatty molecules. This is essential because making stool softer reduces the risks of straining and hemorrhoids.


Gut Stimulants or laxatives


Bisocodyl and Senna are nerve stimulating medications that increase colonic contractions to push stool forward. Overuse of laxatives should be avoided as it can cause abdominal pain, cramping, nausea and vomiting. Prolonged laxative use can cause either constipation or diarrhea due to the dysregulation of the bowels.


Magnesium – Magnesium citrate and Milk of Magnesia cause relaxation of the bowel muscles and moves water into stool making stools softer and easier to pass. Individuals with certain medical conditions may not be able to take magnesium due to risks of electrolyte abnormalities, be sure to consult a physician before taking.


Teas that aid in constipation – Most of the teas that are marketed for weight loss do so by either reducing appetite or constipation.

How tea reduces appetite:

        1. It is hot
        2. High water content fills the stomach and is hydrating
        3. Some teas contain caffeine, a natural appetite suppressant
        4. Increased fluid in the stomach reduces cravings

Herbal teas that contain senna or cascara (dried bark from tree native to Western North America) are laxative teas that push stool forward by stimulating nerves that cause muscle contraction, laxatives should not be overused as they can cause bowel dysregulation.


Will fiber aid in weight loss?

 Yes, it certainly can. Fiber expands in the gut, slows down digestion, and can create feelings of fullness that reduce overeating. Fiber can also stimulate healthy gut bacteria that aid in making digestion easier.


Severe constipation  

If none of the above methods work for constipation you may be suffering from severe constipation and in need of a doctor or specialist. Severe forms of constipation can result from neurological complications such as neuropathy from longstanding diabetes.


Tips for discussing constipation with your doctor

#1 Don’t be embarrassed.

Everyone has or will have constipation at some point, your doctor understands.


#2 Be prepared with a description

Use a journal or notepad to describe exactly what you are experiencing (use our free constipation diary here). The more detail the better.

    • How often you have a bowel movement?
    • What is the color?
    • Is it small, medium, large?
    • Is there blood?
    • Do you strain?
    • Is there pain?

#3 Changes in your diet 

#4 How much water do you drink daily in ounces or cups

 #5 Associated symptoms i.e. bloating, gas, abdominal pain


Your doctor will likely ask about medical history as well as family history to determine risks for certain diseases that may be contributing to constipation. Be sure to share any family history of colon cancer or other conditions.


Have you lost weight just to find that your bowel movements are hard, infrequent, or difficult to pass?


Download our Constipation Log to help keep track of your symptoms.


Top recommendations below: 

Check out our fiber drinks Tropical Fruit Fiber Drink and Lemon Fiber Drink in the Online Store

Fiber Drink





Click here for Tropical Fruit Fiber Drink 


Lemon Fiber Drink





Click here for Lemon Fiber Drink


Psyllium husk capsules – order 180 count of psyllium husk capsules on Amazon here or 400 count of psyllium husk capsules on Amazon here 

Other forms of fiber supplementation (always choose low carb options with zero sugar added):