11 Best Foods to Eat to Prevent Constipation After Bariatric Surgery

Sharing is caring!

Are you struggling with constipation after bariatric surgery? Or maybe you haven’t had surgery yet but you want to help prevent constipation after bariatric surgery?

In this article I am going to share with you what constipation is, why it can occur after bariatric surgery, and the 11 BEST foods that you can eat to help prevent constipation after bariatric surgery. 

What is Constipation?

According to the National Institutes of Health (NIH), ‘constipation is a condition in which you may have fewer than three bowel movements a week; stools that are hard, dry, or lumpy; stools that are difficult or painful to pass; or a feeling that not all stool has passed. You usually can take steps to prevent or relieve constipation.’

As you can see from the definition above, you can be constipated when you have fewer than three bowel movements per week, but you could also be constipated when you are having a bowel movement every day if you have stools that are hard to pass or are dry or lumpy. 

what is constipation: less than 3 bowel movements per week, dry, hard, or lumpy stools, stools that are difficult or painful to pass, a feeling that not all stool has passed

Constipation After Gastric Sleeve vs. Constipation After Gastric Bypass

Both gastric sleeve and gastric bypass surgeries can be affected by constipation equally. Having one surgery over the other won’t increase or decrease your likelihood of constipation after bariatric surgery. For either surgery, you are still going to:

  • Take iron and calcium supplements
  • Likely be prescribed narcotic medication for pain control after surgery
  • Have a decrease in the amount of food (and thus fiber) that you are able to eat in the early days after bariatric surgery
  • Possibly be prescribed an acid reducer/proton-pump inhibitor after surgery

Why Does Constipation After Bariatric Surgery Occur?

There are several reasons why you might experience constipation after bariatric surgery. 

Eating Less Fiber

One that you might have already thought of is low fiber intake because you’re not eating very much food. Unfortunately you can’t always fix this problem because you’re limited in how much food (and thus fiber) that you can eat in those early days after surgery. 

Fortunately though, if you’re eating vegan after bariatric surgery, you may be choosing more foods that are rich in fiber than your omnivorous counterparts. For example, tofu has fiber and meat doesn’t!

There isn’t a specific amount of fiber that is recommended for the early days after bariatric surgery. To help prevent constipation you can choose to eat foods that are appropriate for your diet stage that contain fiber. For example, choose a blended bean soup instead of cheese to increase your fiber intake. 

Later in this article I am going to share a variety of high fiber foods that you can eat to help increase your fiber intake. 

Medications Used After Bariatric Surgery

Narcotic Pain Medications

One thing that you may not think about causing constipation after bariatric surgery is pain medication. Narcotics are often prescribed after bariatric surgery for pain control, but they can cause constipation. 

I am not trying to imply that you shouldn’t take medication for pain control after bariatric surgery, but the possibility that narcotics could cause constipation is something you should be aware of. If you are worried about constipation from taking narcotics after surgery, this is something you should discuss with your bariatric surgery team ahead of your surgery.  

Acid Reducing Medications or Proton Pump Inhibitors

After bariatric surgery it is likely you will be prescribed proton pump inhibitors/acid reducers to reduce risk of ulcers. Unfortunately these can also increase your risk of constipation. This is not necessarily something that you will be able to change after bariatric surgery to reduce your risk but more something to be aware of. 

If you’re constipated after bariatric surgery and are concerned it is a result of taking proton pump inhibitors you should discuss this with your bariatric surgery team. Do not just stop taking prescribed medications without talking to your doctor. 

Decrease in Normal Activity Levels

After having bariatric surgery you may not feel like doing much and as a result your usual activity levels can decrease. Staying as active as you can after surgery is helpful for reducing your risk for constipation after bariatric surgery. 

You will also be encouraged to walk frequently after bariatric surgery to help prevent blood clots. Follow directions from your bariatric surgery team as to how often you should be walking to prevent blood clots. 

Required Supplements

There are some supplements that you have to take after bariatric surgery that can increase your risk for constipation. 


After bariatric surgery it is required for you to take calcium supplements. The amount of calcium you should take varies depending on what type of bariatric surgery you had and how much calcium you are getting from your diet. 

If you had the roux-en-y gastric bypass (RYGB) and sleeve gastrectomy (SG) surgery you need 1200-1500 mg of calcium per day from food and supplements. 

If you had the biliopancreatic diversion with duodenal switch (BPD/DS) you need 1800-2400 mg calcium per day from food and supplements.

To help minimize the risk of constipation from calcium supplements as much as possible, make sure that you are not over-supplementing with calcium. To figure this out, you can track your usual food intake in a food tracker (I recommend Cronometer) for 3-4 days to get your average calcium intake from food. Then you will know how much calcium to supplement with to make up the difference.   


Iron is one of the most common deficiencies after bariatric surgery so it is vital that you take iron supplements after bariatric surgery. Unfortunately iron supplements can also cause constipation. For the most common types of bariatric surgery, RYGB, SG, and BPD/DS, the daily recommended dose of iron supplements is 45-60 mg/day. Taking more iron than what you need can contribute to constipation. 

Certain forms of iron can also increase your risk for constipation. For example, ferrous fumarate is most often prescribed for supplemental iron needs after bariatric surgery, but ferrous sulfate can increase constipation after bariatric surgery. Check with your bariatric surgery team as to which form of iron they recommend for you.

Decreased Fluid Intake

After bariatric surgery you may be surprised at how challenging it is for you to drink enough fluid. You might have been great at staying hydrated before surgery and struggling for every sip after surgery. 

Not drinking enough fluid not only increases your risk for constipation after bariatric surgery but also can make you feel like crap. It may take quite a bit of effort to relearn how to drink enough fluid after surgery. Even though it is difficult it is so important that you make this a top priority. If you’re struggling with hydration you should contact your bariatric surgery program right away. 

Ways to Increase Your Fluid Intake After Bariatric Surgery

set a timer to remind yourself to drink, try different temperatures of beverages, add fruit to water to change up flavor, use popsicles as part of your fluid intake
  • Set an alarm to take a drink on your mobile phone to help you remember to drink.
  • Try different temperatures of beverages. If you used to like cold beverages and that’s not working any longer, try something warm like tea or broth. 
  • Try different flavors of beverages. If plain water is too boring add fruit into your water or use a calorie-free drink mix to add flavor. 
  • Use popsicles to add to your fluids. Even though they’re frozen, they still count.

11 Foods to Eat to Prevent Constipation After Bariatric Surgery


One whole avocado boasts 9 g of fiber and is a great source of heart healthy fats. You can include avocado blended in a smoothie or soup if you need a liquid/pureed option. As you are able to tolerate more foods avocado is delicious on top of salad or whole grain toast. 

Chia seeds

Chia seeds are one of the best sources of fiber out there. Just 2 tablespoons of chia seeds provides you with a whopping 10 g of fiber. That can really make a dent in meeting your fiber needs for the day. 

Like avocado, chia seeds are also a great source of heart healthy fats. 

Try chia seeds blended into a smoothie or soup, mixed into soy yogurt, stirred into oatmeal, or made into a chia pudding. 


Flaxseeds are another easy way to add fiber and heart healthy fats to your diet, just by mixing them into foods you are already eating. For 2 tablespoons you get 4 g of fiber. Try stirring flaxseeds into your cooked hot cereal or sprinkling on top of your salad. They add a delicious nutty flavor. 


So this might seem obvious but you need to drink enough water to prevent constipation. If you’re getting bored of plain water you can add flavor and variety in several ways. 

Add Variety to Your Hydration-Instead of Plain Water, Try These:

  • Herbal Tea
  • Infused Water (add fruit or vegetables to water and let them soak)
  • Sugar-Free Drink Mixes
  • Coffee (yes, coffee does hydrate you!)
  • Broth (even though it is salty, it is okay to have sometimes to meet some of your fluid goals)
  • Popsicles


Raspberries are also a great source of fiber, helping you to meet your daily fiber goals to decrease your risk of constipation after bariatric surgery. They are also delicious! For a double fiber snack, add raspberries to chia pudding. 


Pears are an ideal food to eat to prevent constipation. Not only do they have fiber, they are also a natural source of sorbitol. Sorbitol is a sugar alcohol that can help with constipation by bringing water into the intestines. Pears make a great snack when you pair them with another food like nuts. 


Prunes are similar to pears in that they are a rich source of fiber and naturally-occurring sorbitol. Dried fruit can be tough to tolerate for some people after bariatric surgery, so if you want to try prunes I would recommend waiting until you’re comfortable eating foods with more challenging textures. For many people, this may not be until at least 3 months after surgery. 

If you’re not sure, check with your bariatric surgery program. 


Coffee helps with constipation, not because of fiber, but because it is stimulating to the muscles in your digestive tract, making it easier for you to have a bowel movement. 

If you’re not supposed to have caffeine, don’t worry. Decaf coffee often works too.  


Lentils are another food that provides a hefty amount of fiber. They also provide a significant amount of protein. Any lentils will do: red lentils, brown lentils, de Puy lentils, they’re all great! The other great thing about lentils is that they work for almost any diet stage. 

For full liquids, you can blend up a lentil soup. For pureed, you can enjoy a mashed dahl. Lentils are the perfect texture for a soft diet and for a regular diet in any form. 


Beans come in so many different varieties that they work in almost any dish to add fiber and protein. Similar to lentils you can use them in almost any diet stage. Hummus works for pureed, a bean soup or stew works for soft, and they continue to be a great choice as a filling part of your meal when you get to regular textures. 


Edamame are immature soybeans (remember, soybeans are used to make soy milk, tofu, and tempeh). Delicious on their own, edamame can be prepared easily in the microwave from frozen. You can also add them to other dishes, such as stir fries to increase the protein and fiber content. 

They are also a great option to order when you’re out to eat. I find that many different types of Asian restaurants have them on the menu and they are often served in their pods. Since you have to take the time to remove them from the pods before eating, it helps to slow down the pace of your meal. 

11 BEST Foods to Prevent Constipation After Bariatric Surgery: chia seeds, water, prunes, coffee, avocado, lentils, flaxseeds, edamame, raspberries, kidney beans, pears

What If You Try All of These Tips & You Still Experience Constipation After Bariatric Surgery?

It is possible that you will drink enough fluid, eat enough fiber, and be staying as active as you can after bariatric surgery and you will still get constipated. If this happens to you, reach out to your bariatric surgery team. There are medications they can recommend or prescribe to help.

Sometimes we think that just because we’re following a healthy vegan diet everything will go perfectly; this could not be further from the truth. There are things about a vegan diet (like having more high fiber food choices) that can make it more preventive against constipation, but this may not be enough right after bariatric surgery or if you have a medical condition (such as irritable bowel syndrome) that make you more likely to be constipated.

Don’t be afraid to reach out for help!

In Conclusion

Constipation is fairly common after bariatric surgery, but there are some things you can do to help prevent it. Eat enough fiber, drink enough fluid, be as active as you’re able to be, and ask for help from your bariatric surgery team if you need it.


McRorie Jr, Johnson W., and Nicola M. McKeown. “Understanding the physics of functional fibers in the gastrointestinal tract: an evidence-based approach to resolving enduring misconceptions about insoluble and soluble fiber.” Journal of the Academy of Nutrition and Dietetics 117.2 (2017): 251-264.

Weight Management Dietetic Practice Group. Pocket Guide to Bariatric Surgery. Edited by Kellene A. Isom and Melissa C. Majumdar, 3rd ed., Academy of Nutrition and Dietetics, 2022.

Sharing is caring!

2 thoughts on “11 Best Foods to Eat to Prevent Constipation After Bariatric Surgery”

  1. This is a wonderful article loaded with precise information. I simply loved the content material and accept as true with maximum of your views. Thank you for sharing.

Leave a Comment

Your email address will not be published. Required fields are marked *