Pre Bariatric Surgery Diet

Your Guide to the Pre Bariatric Surgery Diet

The pre-bariatric surgery diet is one the most anticipated events before undergoing weight loss surgery. As a dietitian, I often hear the following concerns:

Will I be able to do it?

What happens if I can’t do it?

What will I be able to eat?

What’s it like?

Today I want to answer these questions for you. I will also be providing you with a sample meal plan at the end of this article that you may find helpful. 

Disclaimer: This material is considered for educational purposes only. Please direct all questions to your doctor. This article contains affiliate links which means I make a small amount of money if you choose to purchase a recommendation.

Why do I need to do the pre bariatric surgery diet?

The purpose of the pre bariatric surgery diet is to help shrink your liver. This allows your surgeon to see better while performing surgery and reduces complications.The diet typically lasts about 7-14 days prior to surgery.

What can I have during the pre bariatric surgery diet?

Most surgery centers require patients to only drink low calorie, sugar and caffeine free beverages in conjunction with an approved protein supplement.

This usually includes the following:

  • Water
  • Sugar-free Popsicles
  • Sugar-free jello
  • Herbal teas
  • Flavored waters like Crystal Light or Propel
  • Miso broth
  • Fruit Infused water
  • Bone broth
  • Broth
  • Approved protein supplement

During this pre-op liquid diet period I typically suggest to aim for 64 oz fluid in addition to the protein supplements. Make sure at least half of your fluids are coming from pure water. I encourage my clients to focus on water, broth, fruit infused waters and herbal teas during this stage and less on products that include artificial sweeteners.

What protein supplement should I use?


Protein supplements are used in the pre-bariatric surgery diet to help preserve your muscle mass. But when you’re looking for a protein supplement the options can be overwhelming. It seems like there's a new protein supplement coming out all the time. My suggestion is to begin using a protein supplement that you will be drinking after bariatric surgery.

The American Society for Metabolic and Bariatric Surgery recommends using a protein drink that contains whey protein isolate. Your body will absorb this type of protein source the best. However egg white, casein, milk and soy are also highly absorbable sources of protein. Look at the ingredient list of your protein supplement and make sure one of these sources of protein are listed. I suggest your protein supplement has at least 20 g protein per 8 oz.

It’s also  important to minimize the fat and sugars in your protein meal replacement as well. My suggestion is to choose a protein supplement that has less than 5 g of sugar and less than 3 g of fat.

Options for good choices of bariatric protein drinks include:

How many protein supplements should I drink?

The amount of protein drinks you consume each day will depend on two things:

  1. The type of protein supplement

  2. Your personal protein goals

Each protein drink contains different levels of protein. As stated before, I suggest choosing a protein drink with at least 20 g of protein per 8 oz. If you choose a protein drink that contains less protein then you will have to drink more protein supplements to meet your protein goals.

Your individual protein goals will be determined by your dietitian. Most surgery centers recommend consuming 60-100 g protein a day. The exact amount varies based on your current weight, height, gender and how active you are. Your dietitian will help you figure this out. But aiming for 70-90 g protein a day tends to be a good bet.

By taking all of this into consideration, most people drink between 3-5 protein supplements a day during the pre-bariatric surgery diet.

How many calories will I be eating?

Most programs do not require you to count calories during the pre-bariatric surgery phase. However, if you are drinking 3-5 protein supplements daily you will likely be consuming 500-800 calories daily.

How hard is the pre bariatric surgery diet?

I am not going to sugar coat it. It’s tough, but I believe you can do it.

My past clients have shared with me that the first three days were the hardest. But knowing that they had a goal in sight kept them motivated. I believe you can do the same. Here are some tips that others who "have been through it" shared with me.

Tips for Success

Have a plan!

  • Purchase all of your protein supplements and fluids ahead of time to help ease your stress load. You can prepare a batch of chicken broth and a pitcher of fruit infused water ahead of time. You could also stock your fridge with sugar-free jello and sugar-popsicles to help prep ahead.

Prepare meals for your family

  • If you typically prepare meals for your family, then it might be tempting to eat while you are cooking. Prepare a batch of meals and store them in the fridge or freezer. Then your family can reheat the food when they are ready to eat. Or encourage your family to prepare their own meals during this time period.

Keep your mind focused on your motivation

  • Remember your motivation for undergoing weight loss surgery. Your personal reasons for wanting surgery can be a source of strength at this time. It may be helpful to write your motivation down. 

Clear your social calendar

  • Everyone has different experiences but many have shared with me that to help them stay focused they cleared their social calendar. They did not want to answer questions why they were not eating or tempted by the smells of foods they could not enjoy.

What happens if I cheat on the pre bariatric surgery diet?

The purpose of the pre-op liquid diet is to help shrink your liver. Your liver is normally surrounded by glycogen. Glycogen is a fuel source for your body. When your body does not get enough calories from food, it begins to use your glycogen storage as a fuel source instead. The glycogen is broken down into glucose so your cells can have energy.

By drinking a very low calorie diet during the pre-op liquid phase, you're forcing your body to use your glycogen as an energy source. As the glycogen breaks down your liver becomes smaller. This allows your surgeon to see more of your abdomen in the operating room and perform the surgery safely. Believe me, you want your doctor to be have a good view of what he or she is  doing.

So in a nutshell, if you cheat on the pre-op liquid diet you’re putting your health at risk and possibly increasing your recovery time after surgery or even risk of death.

With that being said, it’s important to communicate with your surgeon’s team if you did not stick with the pre-surgery diet. Depending on what you ate, they may or may not cancel surgery.

Will I be able to do it?

Yes, absolutely!

 You can do this. 

Develop a plan. I suggest preparing these recipes ahead of time to help you feel more confident going into this diet. 

  • Chicken Broth (because it tastes SO much better than store bought)
  • Fruit Infused Water

It’s also helpful to know what you will be drinking each hour of the day to help you stay on track. See the meal plan below to help you plan out your day.

I also encourage you to talk with others that have been through it. Learning about other people’s experience can help you gain confidence in your ability to complete this stage before surgery.

Pre-Bariatric Meal Plan

Downloadable Pre Bariatric Meal Plan PDF

Would you like this meal plan?

I can send you a copy to place on your fridge to help you stay on target with your goals. Just type in your email. 

    By typing in your email you will be subscribing to my email list. I won't send you spam. Unsubscribe at any time.

    Powered By ConvertKit

    Did you find this article helpful?

    If so, please share it with others in the weight loss surgery community.

    Kristin Willard, RDN

    I am Bariatric Dietitian that teaches you how to eat before and after weight loss surgery to help you feel and look your best.

    >

    Sign up for my newsletter and receive your FREE 1 week free meal plan!