Bariatric PreOp Diet:
The Nitty Gritty Details

For many, the bariatric preop diet sounds intimidating. Allow me to shed some light on a few “WHATs” to alleviate any fears:

  • WHAT you can eat
  • WHAT you can drink
  • WHAT to avoid
  • WHAT to expect

Answers to more “WHATs and WHYs here.”

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Bariatric PreOp Diet:
WHAT Will I Be Able to Eat?

The preoperative diet menu typically consists of:

You may also possibly be allowed non-starchy, low carbohydrate vegetables or a “lean and green” meal that consists of lean protein and green vegetables.

There are no standardized guidelines for the bariatric preop diet, so recommendations vary vastly between surgeons. However, the goal of the bariatric preop diet is always the same: reduce the size of your liver. 

A sample day in a 2 week ALL LIQUID pre op liver shrinking diet menu might look like this. Use 5 bariatric specific meal replacement shakes every 3 hours. Drink water or acceptable low calorie beverages in between and sprinkle in the “free” foods as needed:

Sample Meal Plan

  • 6am: Wakeup. 8 ounces water and black decaf coffee or tea
  • 7am: Meal Replacement Shake
  • 8am: 8 ounces water or low-calorie beverage
  • 9am: 8 ounces water or low-calorie beverage
  • 10am: Meal Replacement Shake
  • 11am: 8 ounces water or low-calorie beverage
  • 12pm: 8 ounces broth
  • 1pm: Meal Replacement Shake
  • 2pm: 8 ounces water or low-calorie beverage
  • 3pm: Sugar free popsicle or sugar free gelatin
  • 4pm: Meal Replacement Shake
  • 5pm: 8 ounces water or low-calorie beverage
  • 6pm: 8 ounces water or low-calorie beverage
  • 7pm: Meal Replacement Shake
  • 8pm: Sugar free popsicle or sugar free gelatin

Note: Adjust times based on your own personal schedule.

See more on HOW to follow Pre Op Liquid Diet

Bariatric PreOperative Diet:
WHAT to Drink

Be sure to drink AT LEAST 64 ounces of no calorie or low calorie beverages. You can see in the sample menu above how it’s possible to fit it all in when you have a plan!

Drinking more than 64 ounces is ok too. You might even plan to do so, as it helps curb hunger.

Water is definitely the best beverage, but you can also drink Crystal Light, Bai water, Vitamin Water Zero, Powerade Zero, or other low calorie beverages like these. You can also add any sugar free flavoring to water or drink fruit infused “spa” water.

If you “don’t like” water, try drinking Alkaline water. I guarantee you’ll become a water lover!

Bariatric PreOp Diet:
WHAT Will I Have to Avoid?

Avoid these Beverages:

  • Alcohol (all beer, wine, liqueurs, spirits)
  • Fruit juice (all)
  • Soft drinks (including zero-calorie varieties)
  • Sugar sweetened beverages
  • Specialty coffee drinks (mochas, etc.)
  • Fruit smoothie drinks

Avoid these Condiments:

  • Cream based sauces, toppings, dressing, and condiments
  • All salad dressings

Caffeine: may or may not be allowed depending on your surgeon’s guidelines. Truthfully, caffeine does not affect the size of your liver. But cutting out the sugar and/or flavored creamer you may add to your coffee WILL help!

Carbonation: Your bariatric surgeon may recommend you also avoid carbonation on the bariatric preoperative diet. Doing so will help you get prepared for the post op period when you MUST avoid carbonation while you heal. However, carbonation itself doesn’t affect the size of the liver. Full sugar carbonated drinks DO however!

Pre Surgery Diet:
What to Expect on the PreOp Liquid Diet

The two-week pre op diet can be mentally challenging as well as physically challenging.

So prepare yourself for the challenge. Tell yourself, “this is temporary, it’s ONLY 2 weeks. I can do anything for 2 weeks.” Take it day by day. Hour by hour if needed. It’s simply a means to an end. It’s not going to last forever.

Don’t get caught by surprise! You may experience any or all of the following symptoms while on the 2 week pre op diet. When carbs and total calories are restricted, you may have:

  • Hunger Pains
  • Fatigue
  • Headaches
  • Constipation
  • Mood Swings

These symptoms are “normal” or “expected” during the bariatric preop diet. If you experience any of these symptoms, just know they usually subside within a few days after your body gets used to the reduced calorie and carbohydrate levels.

Helpful Tips:

If you experience any of the symptoms mentioned above:

  • Drink MORE than 64 ounces of no calorie or low calorie beverages to help with hunger.
  • Drink hot or warm beverages or broth. The warmth helps you feel full.
  • Use the “freebies:” sugar free jello, sugar free popsicles, and broth. They help curb huger and help you feel like you’re “eating” something.
  • Reach out for support if you need it. I’m happy to help!
  • Call your surgery practice as needed.

Answers to Many More Important Bariatric PreOp Diet “WHY” and “WHAT” questions


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