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Pre-Op Liquid Diet: Two Weeks Before Bariatric Surgery

Approximately two weeks before surgery, your doctor will start you on a full-liquid, low-carbohydrate diet. Your physician will specify exactly when you should start the diet. If you're diabetic, your doctor may decrease your insulin/diabetic medications during this time.

In addition to protein shakes, you should aim for a fluid intake of 64 ounces per day. You should also avoid drinking through straws.

The liquid diet serves several purposes. First, it helps you lose some weight before surgery, which reduces the risk of your laparoscopic surgery having to be converted to open surgery. It also reduces your liver size, intra-abdominal fat, co-morbidities, operating time, recovery time, and post-operative risks.

Your liquid diet should consist of:

  • At least three protein shakes per day (200 calories or less each; protein should be higher than carbohydrates; if using protein powder, mix with water, soy milk, or skim milk):
    • Atkins
    • Pure Protein
    • Premier Protein
    • Spiegel Slim
    • Light Muscle Milk
    • Isopure
    • EAS Advantage
    • Body Fortress
    • Jay Robb
    • Vega
  • Water (any sugar-free water additive can be used)
  • Propel Water
  • Vitamin Water
  • Unsweetened tea (alternative sweetener can be added; Stevia or monk fruit is best)
  • Unsweetened black coffee (alternative sweetener can be added; Stevia or monk fruit is best)
  • Diet Snapple
  • Zero-calorie, non-carbonated drinks
  • Skim milk
  • Chicken or beef broth
  • Nonfat plain yogurt
  • Sugar-free pudding
  • Sugar-free Jell-O
  • Sugar-free popsicles

Avoid the following liquids:

  • Carbonated beverages
  • Alcoholic beverages
  • Boost and Ensure protein shakes
  • Special K or Slim Fast shakes
  • Smoothie King or any fruit/dairy smoothies
  • Fruit or vegetable juice

It's very important that you adhere to this liquid diet according to your surgeon's instructions. There have been cases in which a patient's surgery was canceled due to noncompliance with the pre-op diet. If you find yourself struggling with the guidelines, contact your bariatric team for help.

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