Constipation and Weight Loss Surgery

Whilst not uncommon following weight loss surgery, is not something we tend to feel comfortable in speaking about. It is however important to feel you can speak freely about this topic to your dietitian and bariatric GP, as it is an important issue that needs discussion and management.

What is Constipation?

Naturally when you are eating less food after weight loss surgery, it becomes normal for less to come out. This does not mean you are constipated. Constipation is not only about how often you go, but rather how you go and the consistency of your stool. After surgery it can be common not to open your bowels for three or four days. Going less often, but with ease, is fine and not defined as constipation. However, if you feel you need to go but can’t, or you are getting a sore tummy, or you need to strain to go, this is likely constipation, even if you are able to pass stools daily.

Looking at the Bristol Stool Chart below, our goal is to aim for a Type 3 or 4, however this depends on your stage post-surgery. Type 1-2 suggests constipation and that you may need extra fibre, fluid, or physical movement. However, it is important to discuss this in detail with your dietitian, as these recommendations may not be appropriate or possible for you during your early stages of recovery.

Bristol Stool Chart



Managing Constipation in the Early Post Surgery Phases

Constipation can often be resolved simply by tweaking some everyday habits and this is always the best place to start. Consider the following the ‘fundamentals’ of constipation management.


If you are constipated, firstly reflect on your fluid intake. Aim for 1.5L per day. This can be challenging in the early phases. Remember to sip, sip, sip and chat to your dietitian if you are struggling and need more ideas to keep well hydrated. The following strategies can help you stay hydrated during this time:

  • Sip, sip, sip throughout the day. Always keep a drink with you.
  • Try flavouring your water with diet cordial, cold brew tea infusions, slices of lemon, frozen berries or frozen juice cubes.
  • Herbal teas and warm broths count as fluids as well – having a warm drink in the morning can help get your bowels moving.

It can also be useful to reduce your intake of caffeinated beverages as caffeine can make you more dehydrated. Aim for no more than two caffeinated drinks per day.


Fibre can help with constipation by drawing water into your gut and also adding bulk, making your stools softer and easier to pass. Add in as many natural fibre sources as possible to your diet including fruits, vegetables and legumes. The following strategies may be useful:

  • Blend fruits and vegetables into soups and smoothies whilst on the fluid diet phase. Make sure the soup/smoothie is thin enough that it could get through a standard sized straw.
  • Mash or puree fruit and veg to the texture of silky-smooth mashed potato whilst on the puree diet phase.
  • Try adding plant-based sources of protein such as lentils and chickpeas to soups and purees to boost both your fibre and protein intake.
  • Include a kiwi fruit daily. Studies have shown that the fibre and enzymes found in kiwi fruit work together to promote healthy bowel movements.


Sorbitol is a type of sugar found in fruit that we can’t digest. It moves through your bowels and helps draw water into your stool, acting as a gentle laxative. Fruits high in sorbitol include apples, apricots, avocado, nectarines, peaches, plums, pears and prunes (including their juice varieties). Try including one serve of any of these fruits each day. Be sure to be mindful in choosing the appropriate textures of these depending on your recovery phase.

Fibre Supplements

We often recommend Benefiber or Feel Good Tasteless Fibre, as these are suitable to use during the fluid recovery phase and beyond. Make sure you are also drinking at least 1.5L of fluid each day when using these. Benefibre and Feel-Good Tasteless Fibre are not laxatives, meaning they don’t have an instant effect. Therefore, if you are not drinking enough, it can dry out your stools, making them harder to pass. Ideally, these supplements need to be included regularly over a long period of time with ongoing adequate fluid intake to be effective. Again, try to sip, sip, sip fluids when you are not eating.

Some may find the following DIY homemade fibre supplement useful.

75g Allbran
250g Apple Puree or apples, pureed 75g prunes, pureed
50ml orange juice

Blend all ingredients, adding more juice if required. Store in the fridge or freeze in ice cube trays. Include a tablespoon at a time or as ice cube sized serves. Include 1-2 serves daily.


Exercise can help with constipation by reducing the time it takes for food to pass through your bowels. Be mindful of restrictions around exercise in the early days after surgery. You could try 10-20 minutes of gentle walking or riding on an exercise bike after from two weeks following surgery.

Additional Steps

If you’ve been working on the fundamentals above and are still having trouble with constipation, following are some additional strategies you can try.


It is essential that you have a chat to your Bariatric GP, Nurse or Surgeon before commencing laxatives to determine the best option for you, including the potential use of suppositories and/or enemas. The effectiveness of laxatives can be highly individual and require some trial and error, which is best supported by a medical professional.


Over time, certain strains of pro-biotics can help promote a healthy gut that works at its best, and this can help reduce constipation. Studies have shown that lactobacillus plantarum is a helpful strain for managing constipation. This is found in the Swisse IBS probiotic, or you can look for brands that contain a broad spectrum of strains such as Lifespace.


Make sure you are allowing enough time, about 10 minutes, to sit on the toilet in an environment where you feel comfortable and relaxed. You may need to get up ten minutes earlier in the morning so you have time to open your bowels.


Consider using a foot stool whilst sitting on the toilet. Placing it underneath your feet creates a much more natural position for the body, hopefully creating some ease.

It’s important to know that these suggestions may not work for everyone Each person’s bowel is a little different, and what works to relieve constipation for you can be a bit of trial and error. If you’re concerned about your bowel function, or it’s causing pain, please contact your bariatric GP.

Managing Constipation Long Term

If you are experiencing constipation on a regular basis a year or two after surgery, try the following:

  • Ensure you’re getting 20g or more of fibre (including sorbitol sources) in your diet and one and a half to two litres of water daily.
  • Include regular exercises/stretches that rotate your abdominal area.
  • Be mindful of how stress might be affecting your bowel.
  • Reduce your caffeine and alcohol intake.

If you need further support, you can speak with your dietitian to help individualise your diet and/or identify a possible underlying food intolerance. You could also book in with your GP to discuss any possible side effects of medications you are taking and or discuss the need for a gastroenterology referral.

High Fibre Sample Meal Plan

Breakfast: ¼ cup oats (2g fibre) with 200g yoghurt and 3 prunes (2g fibre PLUS sorbitol)

Morning tea: ¼ cup mixed nuts (2.5g fibre)

Lunch: ½ cup spiced Mexican beans (7g fibre) with ½ cup baby spinach (2.5g fibre) and ¼ avocado (3.5g fibre) in a wholemeal wrap or on Vita-Weat (2.5g fibre)

Afternoon tea: Home-made protein ball (0-1g fibre)

Dinner: 80g chicken with ¼ cup mashed sweet potato (1g fibre) and ¼ cup broccoli (1.5g fibre)

Total fibre: 25.5g

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