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  3. Pre-Op Bariatric Diet – Know it All

Pre-Op Bariatric Diet – Know it All


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Question How Long Will I have to Follow the Pre-Op Bariatric Diet?

Answer – Generally, the pre-op weight loss surgery liquid diet should be religiously followed for 3 days to 3 weeks depending on the individual. (Disclaimer: Please do not take the information as medical advice and consult your doctor.)

This is general information based on suggestions by our Mexico bariatric program and it has to be customized for each individual.

The main purpose of the liquid diet is to help shrink your liver so that it is easier for the surgeon to perform your bariatric surgery. Hence, this diet is also known as the liver shrink bariatric diet.

Diet Before Bariatric Surgery

How to Follow the Diet

According to Cleveland Clinic1, pre-op bariatric diet should commence 2 weeks before surgery. The clinic states that:

  • In the first week of the diet, one meal out of the three should comprise of protein shakes (low in sugar and high in protein).
  • Nutritional supplements, Nonsteroidal anti-inflammatory drugs (NSAIDs) are strictly not recommended.
  • In the second week, no solid foods are to be consumed and all meals are to be replaced with protein shakes supplemented with clear liquids in between. Here are some calorie-free options for pre-op liquid diet.
  • 24 hours before the surgery, a full-fledged clear liquid diet is to be followed.
  • Do not eat or drink anything after midnight, the night before your surgery.

The main idea is to have a liver shrinking diet that is rich in protein and low in carbs so that the excess fat stored in the liver is burned for energy as opposed to muscle tissue.

Pre op Bariatric Diet

Work with A Dietician

Take guidance from a registered bariatric nutritionist who will identify your individual requirements and help you get the best results out of the proposed pre-op diet.

He or she will guide you as to when you need to start with the liquid diet, what liquids will be the best and how you should be taking them.

Find a sample menu for pre-op diet to be followed 8 days before gastric sleeve surgery under the “Article Attachments” section.


  1. “Nutrition Manual.” Cleveland Clinic – Bariatric and Metabolic Institute, https://my.clevelandclinic.org/-/scassets/files/org/florida/digestive-diseases/bariatric_nutrition_manual.ashx?la=en
  • Diet before gastric bypass
  • Pre-op diet for gastric sleeve
  • Shrink fatty liver
  • Pre-op methods to reduce size of liver
  • What can you have on a liquid diet before surgery?
  • For how long does liver reduction diet continue?

Article Attachments

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