Why Do I Need A Liquid Diet Before Bariatric Surgery?

You’re considering bariatric surgery, but you have some questions about the liquid diet that is required before surgery. What is it, and how long will you need to be on it? Why is it so important?

In this article we’ll walk through those questions together.

Understanding the Importance of the Liquid Diet

You’ll need to adopt a liquid diet for 1 full week before your surgical procedure as part of your preoperative diet. This shrinks the liver. The liver actually rests on top of the stomach, which means that during surgery we need to move the patient’s liver in order to gain access to the stomach. The liquid diet makes this easier. 

The liver ordinarily stores the carbohydrate glycogen. After only imbibing liquids for a week, the glycogen will leave your liver (as will some water), which makes the liver softer, more flexible, and also smaller. This makes your surgical procedure easier and safer. At a certified ASMBS comprehensive MBSAQIP center like the BMCC, your surgery is already as safe as any minor outpatient surgery. However, it’s very important to us to minimize the (already small) risk of complications, and asking patients to adopt this diet before surgery is one way that we do this.

This diet also removes some fatty tissue, some of which is stored in the liver when patients have fatty liver disease. As a result, this diet also  can decrease the size of a fatty liver and makes weight loss surgery easier and safer. One study found that patients who adopted a very low calorie diet, such as the liquid diet, had a substantially lower complication rate compared to those who did not.

Benefits of Adhering to a Liquid Diet Pre-Surgery

This diet will help improve your recovery time. At the BMCC, our patients often experience a very rapid recovery time, and are able to safely and comfortably go home the same day of surgery and often return to work 2 weeks after surgery. One reason for this rapid recovery is the liquid diet. It will be high in protein, which is needed for wound healing and can speed up recovery substantially.

Another benefit is that this diet will ensure that the patient’s stomach is empty and shrunken before surgery. If food is in the stomach, it can raise the risk of complications by introducing another variable to the surgery.

What happens if you don’t do the liquid diet before weight loss surgery? Unfortunately, you’ll be at a higher risk of complications and your surgery may take longer due to the larger liver that can impede surgical visibility. Your recovery may also take longer. For these reasons, we require our patients to adopt this diet for one week before surgery. However, if you have baseline chronic kidney disease or renal failure, this diet can stress your kidneys. For this reason you should clearly communicate your kidney condition with your bariatric surgeon as a modification may be needed in some cases to protect your kidneys.

What Does the Liquid Diet Consist Of?

Your nutritional intake will change substantially for this week: your diet will be low in fat, sugar, and carbs; and high in protein. While every patient’s diet is unique, this phase of your preoperative diet will probably entail:

– vitamin reinforced protein drinks (you’ll need to consume 80-100 grams of protein per day)

– low-sodium broth

– water

– sugar-free popsicles

– caffeine-free (herbal) tea

On this diet, you should avoid:

– sugary drinks

– carbonated beverages

– caffeine

– alcohol

This diet can be hard to stick to, because you may be hungry and craving food. It’s important to keep your eye on the larger goal. Weight loss surgery is not an easy solution, but it is a powerful way to level the playing field in your battle with obesity. Many of our patients lose 100-150 pounds or even more and keep it off, and no longer feel like prisoners in their own bodies. This part of your preoperative diet is a key part of this process.

Taking the Next Step On Your Weight Loss Journey

If you’re ready to take the next step on your weight loss journey, we encourage you to schedule a bariatric assessment with us. Our team includes a bariatric dietitian who will offer you personalized diet guidance to optimize your nutritional intake both before and after surgery. We care deeply for our patients and our entire team will be with you on every step of your journey both pre- and post-surgery.

Our patients routinely say that surgery was the best decision they ever made.

“I feel like I have won the lottery and have been given a second chance in life! March 25, 2014 was the first day of the rest of my new life and I can’t even start to express in words how grateful I am.”—Rochelle Goforth, patient.

If you’re suffering, don’t wait. Contact our Denver office today.

Dr. Joshua Long headshot

This page was medically reviewed by Dr. Joshua Long, MD, MBA, FACS, FASMBS. Dr. Long is a double-board-certified bariatric surgeon and bariatric medical director for Parker Adventist Hospital.
Full Bio: Dr. Joshua Long, MD, MBA, FACS, FASMBS
Page Updated: December 19th, 2023

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