Join Facebook Group

As an Amazon Associate, BariBuilder earns from qualifying purchases.

Gastric Bypass Liquid Diet

Gastric Bypass Liquid Diet

Gastric Bypass is a helpful weight loss surgery tool that allows adults to lose excess weight in a healthy, controlled manner.  To better prepare your mind and body for the best success before and after surgery, you must have a maximum of two weeks of liquid diet and a minimum of a one-week liquid diet to prepare for surgery.

The main reason you must have a pre-surgery liquid diet is to shrink your liver.  Your liver and stomach are both close-in location to each other.  When you have an enlarged liver, it is more challenging for your bariatric surgeon to safely operate on your stomach and perform the surgery with minimal risks.

To adequately shrink your liver before surgery, you need to eat a maximum of 800 calories daily to shrink your liver to a recommended size.  The average amount of time you will be spent on this liquid diet is ten days.

Gastric Bypass surgery teaches your stomach how to eat smaller amounts of food that allow your stomach to digest safely.

This surgery also helps you lose weight safely and avoid regaining weight.

Recommended Gastric Bypass Liquid Diet:

These include:

  • Water = 0 Calories
  • Protein Supplements = 75-200 Calories
  • Decaffeinated Tea/Coffee = 5-10 Calories
  • Sugar-Free Beverages = 0-20 Calories
    -Crystal Light
    -Vitamin Water
  • Vegetables:
    -Vegetable Juice
    -V8 = 50 Calories
  • Fruits:
    -None Allowed
  • Breads:
    -Cream of Wheat = 130-150 Calories
    -Cream of Rice 130-150 Calories
  • Soups
    -Broth/Bouillon  = 10-20 Calories
  • Yogurt
    -Dannon Light and Fit = 80 Calories
    -Yoplait Light = 90 Calories
  • Sweets
    -Sugar-Free Ice Pops = 15-30 Calories
    -Low-Fat Sugar-Free Pudding = 60 Calories
    -Sugar-Free Gelatin = 20 Calories
Soup is a safe alternative to other clear liquids.

All of these are great food suggestions that will help you maintain your liquid diet and prepare your body before surgery.

Post Surgery Gastric Bypass Liquid Diet

Day 1 and Day 2: Bariatric Clear Liquids

Immediately after surgery, your stomach is healing from surgery and is tender.  Because of this state, you cannot eat regular food for a couple of months.  Your first two days, you begin with only a gastric bypass liquid diet that consists of clear liquids.  The liquid allowed is:

  • Water, Crystal Light
  • Flavored Sugar-Free Water
    -Vitamin Water
  • Decaffeinated Coffee/Tea
    -Iced or Hot
  • Low Fat Broth
  • Diet Jello
Jello is a fun treat that is low in calories.

You must avoid caffeine, carbonation, soda, sugar, and straws.  Your bariatrician will also require you to sip small amounts of fluid throughout the day and slowly.  You cannot use a straw when sipping because they may make you feel bloated and increase gas.  Your fluids will empty more smoothly when your stomach swelling improves.

You also must avoid sugar because sugar adds calories to your diet, which will slow your weight loss and make you feel uncomfortable.

You cannot drink carbonated beverages because they will cause pain and bloating in your stomach and digestion system.

Flat soda is not allowed either because the trapped air bubbles release in your new pouch and cause bloating.

Day 3 to 9: Bariatric Full Liquids

This full liquid diet lasts about a week after surgery, and the consistency of the foods is similar to soup, where it can pour off a spoon.  The foods you are allowed are:

  • Skim or 1% Milk
  • Almond Milk Unsweetened
  • Cream of Wheat or Rice
  • Low-Fat Sugar-Free Pudding
  • Protein Supplement
  • Light Blended Yogurt
  • Sugar-Free Popsicles/Jello
  • Broth
  • Vegetable Juice
  • V8
Maintaining your hydration is important during this time.

During this period of your diet, you must continue to sip your liquids slowly and make sure you are drinking food that is low in fat and sugar.  You will also begin your protein supplements and track your protein intake.  Your dietitian will tell you what your body must consume daily.

This range typically falls between 50-80 grams for women and 60-90 grams for men. It is also important for you to drink 64 oz of liquid daily to prevent dehydration.

It is recommended you have one meal every 2.5 hours and have at least six small meals spread out throughout the day.

Your Gastric Bypass Liquid Diet for a Day:

  • Breakfast: ½ cup of thin cream of wheat.  ½ cup of skim milk.
  • Morning Snack: Protein Supplement
  • Lunch: ½ cup of blended low-fat cream soup.
  • Afternoon Snack:  Protein Supplement
  • Dinner: ½ cup of low-fat cream soup
  • 4 oz. light vanilla yogurt

Why is Protein Important During a Gastric Bypass Liquid Diet?

To reach your daily protein during the all liquid stage, you need to drink two protein supplements to ensure you are getting enough nutrition.  Protein is the heart of your meals and must be the focus.  During this period of time, you will learn how to create a proper bariatric diet by choosing protein, adding veggies, fruits, and some whole grains as you move through the stages.

Protein is the building block for all your cells and energy.  By consuming more protein, your body is not relying on burning up its sugar and will eventually burn your fat.  Burning excessive weight is crucial in weight loss, and protein is essential during this process.  Protein also improves your cognitive functioning.  Your memory and mood will improve as you lose weight.

Liquids and proteins are the most important aspect of your new diet.

Health Goals During Gastric Bypass Liquid Diet

The most important goals you need to consider throughout this liquid dieting process proper healing and learning how to improve your diet.  After surgery, your body is adjusting to a new normal and the nutrients that support your healing.  During this time, your digestive system is slowly moving back to normal.  Your food choices focus on simple and easy to digest ingredients.

This helps in your meal planning choices in the future.

By changing your diet, your taste buds also evolve.

Because you are eliminating sugar from your diet and focusing on protein, your body lowers its blood sugar levels and expand its food choices.  You will also be able to maintain hydration due to the liquid centered diet, which will be essential in your diet plan.

What is the New Normal?

During this liquid stage,  you can form great new habits by changing your taste buds and resetting bad habits.  This is a learning experience that will allow you to grow and change from your past.

After progressing and graduating from your all liquid diet plan, you will begin introducing different foods.  During this process, you need to focus on eating and drinking slowly. A fundamental rule for bariatric eating is waiting 30 minutes after your last drink to 30 minutes after you finish eating to begin drinking again.  Because of this rule, you need to learn how to implement meal preparation and manage your time when it comes to eating and drinking.  If you do not follow this rule, you will overeat and regain weight quickly.

Along with waiting before and after your meals to drink the liquid, you need to make sure every meal is small, where you chew your food slowly and thoroughly.  It is easy to overfill your plate and eat too quickly; therefore, a trick is only to use small plates.  This makes your mind think your portions are enough and not too small.

Overall you will make mistakes along the way as you adjust to new habits, but having an active support system is critical as you move throughout this process.  It will be challenging at times, and having others you can share your experiences with will help you adjust and learn to enjoy your new life.

Want to discuss this article or ask a question? Join our Facebook community of peers just like you.

Kelsey Renae Schulze


Kelsey is a post-op bariatric patient who had sleeve surgery in 2018. She is a writer, focusing on a variety of topics given her background in legal studies and criminal justice.