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Common Side Effects After Bariatric Surgery – Part 1

Common Side Effects After Bariatric Surgery – Part 1

Patients experience varying degrees of symptoms or side effects following bariatric surgery, some of which your surgeon or dietitian will discuss with you at your initial appointment. Some of the more common and immediate side effects include:

Changes in bowel movement regularity

Changes in bowel movements after bariatric surgery may be a result of:

  • A decrease in fibre and fluid intake
  • Lack of movement and exercise
  • Consumption of pain medication or iron supplements which have been linked to constipation
  • Reduced food intake
  • Development of lactose intolerance. Symptoms include bloating, increased gas production, cramping and diarrhoea
  • A liquid diet in the first 2 weeks after surgery result in very little faeces forming, thus it is not bulky enough for an adequate bowel movement.

To help with constipation, try sipping on 100ml of pear or prune juice every morning. Alternatively try Benefibre, but only if you are drinking over 1.5L of fluids. Lastly, an over-the-counter laxative should also help relieve constipation.

To help with diarrhoea, try switching to lactose free dairy products for 2 weeks. Avoiding high fat and sugar foods/liquids may also help until the diarrhoea settles. In the interim, keep up with your fluid intake and intake of oral rehydration drinks if diarrhoea persists. If severe, please contact your GP.

Abdominal pain

The feeling of stitch pain is generally very common in the early weeks after bariatric surgery, and tends to improve after 1-2 days of onset. It is mostly due to the anchoring of the stomach, however may also occur for a number of other reasons such as:

  • Drinking or eating too quickly
  • Taking large mouthfuls of fluid or food
  • Eating and drinking at the same time
  • Doing too much physical activity, especially in the first 6 weeks post surgery
  • Lifting over 5kg.

Pain, discomfort or dull cramping around the incision sites are expected for 3-6 weeks or sometimes even longer after bariatric surgery. This is especially common after gastric bypass as it is a bigger and more involved surgery. Pain medication prescribed by the hospital may help lessen the pain.

Flatulence and gas pain are also commonly seen in the first few weeks post bariatric surgery. Light walking and the use of heat packs may help dissipate any leftover gas used during the operation.

Notify your healthcare team if your pain is severe or prevents you from your day-to-day activities.

Nausea / vomiting

Reasons for nausea include:

  • Dehydration
  • Taking large gulps of fluid or large mouthfuls of food
  • Inadequate chewing
  • Eating and drinking at the same time
  • Taking your bariatric multivitamins on an empty stomach. Instead, try taking it with or after a meal
  • An increase in pain medication.

For any particular concerns about post bariatric symptoms, please get in touch with either your local GP or our dietitian on 07 3871 2277 or email

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