Bariatric Surgery Pre-Op Diet Guide

The purpose of this nutrition guide is to help shrink your liver prior to surgery by depleting stored glycogen. The goal is to consume 2-3 meals of solid, macronutrient-rich foods per day. These whole meals will stay in your stomach longer keeping you full. In addition, use protein shakes as a supplement snack, generally, 1-2 protein shakes per day.

You can download/print the full PDF version here

Pre-Op Diet Guidelines Based on BMI

Start the pre-op diet based on your current BMI.

  • 30-32 =  2 days clear liquids only

  • 33-39 = 1 week including two days of clear liquids

  • 40-45 = 2 weeks including two days of clear liquids

  • 46-49 = 3 weeks including two days of clear liquids

  • 50-59 = 6 weeks including two days of clear liquids

  • 60+ = 8 weeks including two days of clear liquid

Bariatric Surgery Pre-Op Diet Guidelines Based on BMI

General Pre-Op Diet Overview

  • Aim for 2-3 meals of solid food, this will stay in your stomach longer keeping you full.

  • 1 – 2 protein shakes per day -You may purchase these in any health food store or many grocery stores. Please be sure it contains at least 20 grams of protein per serving.  Sugar should be 5 grams or less.

  • You can eat as many raw or cooked non-starchy vegetables as you want (no potato, corn, peas, or winter squash)

  • Two 4 – 7 ounce servings of lean protein (chicken, turkey, fish, lean ground beef)

  • 1 – 2 servings of healthy fat (salad dressing, olive oil, nuts, avocado, olives)

  • You can have ½ a cup of frozen berries, ½ a banana, or 1 apple daily for fruit

  • You can make your shake with unsweetened vanilla almond milk or unsweetened coconut milk (NO regular milk: too much sugar)

  • NO bread, rice, oats, pasta, refined grains, tortillas, sauces with sugar, and no dairy/plant-based (milk, yogurt, cheese), with the exception of unsweetened almond milk and unsweetened coconut milk.

  • NO alcohol, marijuana, or THC products two weeks prior to surgery. These increase bleeding risk.

  • Weight Loss Magic Soup Recipe – Great Vegetable Soup

  • STOP nicotine products 2 months before surgery. Ask your primary care provider for Chantix and Wellbutrin. These two medications taken together are highly effective in stopping nicotine cravings.

  • OPTIONAL: Start taking a probiotic 6 weeks prior to surgery or as soon as possible. You want one that has a minimum of 50 billion units and the more strains the more effective and discontinue 2 weeks before surgery.

Approved Foods

Approved Protein, Vegetables, and Fats - Bariatric Surgery Pre-Op Diet

Important Restrictions

  • Discontinue ALL consumption of Dairy, Starches, Sugars, Desserts, and Fruit (with the exception of 1/2 cup berries or 1/2 a banana daily)

  • Discontinue drinking ALL caffeine 2 weeks prior to your surgery date. Caffeine is a diuretic, may cause dehydration and is acidic. You may drink decaffeinated coffee. Please ensure to stay hydrated.

  • Discontinue ALL carbonated beverages (including sparkling water)

  • Avoid: Ginseng, Ginger, Garlic and Omega 3 supplements. These increase bleeding risk. You may consume small quantities of garlic and ginger in cooking

  • VERY IMPORTANT: Begin the practice of NOT drinking 30 minutes prior to/during/post meals. This should become a LIFELONG HABIT.

14 Days Prior to Bariatric Surgery
(Regardless of Pre-op Diet Length)

  • Vitamins and herbal supplements must be stopped 2 weeks prior to surgery (based on your surgery date).

  • Discontinue birth control and FEMALE supplemental hormones (IUD’S & IMPLANTS ARE TOTALLY SAFE and do not need to be removed).

  • Discontinue drinking ALL caffeine 2 weeks prior to your surgery date. Caffeine may cause acid reflux post-op due to the acidity. You may drink decaffeinated coffee/tea. Please ensure to stay hydrated.

  • Discontinue the use of alcohol, marijuana, or THC products two weeks prior to surgery. These increase bleeding risk.

7 Days Prior to Bariatric Surgery

  • Some medications may need to be discontinued before surgery depending on the instructions of your SURGEON.

  • Specific medications to STOP: Coumadin, ANY ANTICOAGULANTS, OR BLOOD THINNERS Plavix, Aspirin, Ibuprofen, Motrin, Advil, Nuprin, Aleve or any other nonsteroidal anti-inflammatory medication. *Remember this also includes baby aspirin and most arthritis medications. As these can cause stomach irritation and possible more bleeding postoperatively.

  • If there are any medications you need to stay on, talk directly with our surgeon liaison.

For Diabetes Patients

  • May continue to take medication up to the day of surgery. Be mindful, medications and amounts may change due to diet and weight loss change prior to surgery.

  • MUST consult with their doctors about medication use.

  • MUST check sugar levels at home. If sugar is above 150 call your primary care physician immediately.

2 Days Prior to Surgery – Begin Clear Liquid Diet

  • Consume only clear liquids

  • Clear broths: Chicken, Vegetable, or Beef.

  • Water or Flavored Water.

  • Sugar-free drinks such as crystal light and Powerade zero.

  • Sugar-free popsicles and sugar free jello

  • Protein waters like Gatorade Zero with Protein, Isopure Clear, Premier Clear, Protein20

8 Hours Prior to Bariatric Surgery

  • Absolutely nothing to drink after the midnight preceding surgery or 8 hours prior to your surgery.

  • Absolutely NO medications unless directed by the doctor. (If you have been pre-approved to take any medications by your physician leading up to surgery, you may take small sips of water for swallowing.)

  • Please bring ALL your prescribed medications (whether you are currently taking them or not) in properly labeled pharmaceutical bottles for documentation during Pre-Op testing. Do NOT take any medications after surgery until you have consulted with the doctor(s) and gotten approval.

Sample Pre-Op Diet Meal Plan

Here is a sample meal plan to help you get started on the pre-operative diet. This is an ‘example’ of what your day could look like:

  • Breakfast: Options include 2 Whole Eggs, 1/2 an avocado, 1 Cup of Spinach (Raw or Cooked), or 1 Protein Shake

  • Mid-morning snack: 1 Protein Shake (limit 1-2 per day)

  • Lunch: Raw or cooked vegetables (you can add one TBSP olive oil or butter spray to veggies) and 4 oz.  lean meat. Example: 4 oz (110g – 170g) of lean protein, 2 Fist size of vegetables (fibrous carbs), 1-2 thumb size of fats

  • Dinner: Salad with Protein (chicken, fish, egg, etc.), a small amount of no or low sugar dressing (preferably olive oil & vinegar or Lemon)

  • Evening Snack: Apple slices with Almond Butter or Vegetables with Hummus

  • You may also add 1 TBSP chia seeds to your shakes or take psyllium husk to help you stay satisfied throughout the day.

  • * Patients with higher or lower BMI and/or other medical conditions may be prescribed other dietary prerequisites in addition to the above pre-op diet.

  • * You may at this time drink other drinks as long as they have NO SUGAR

Recommended Protein Powders

Ideally, you want to get your protein intake from real foods. However, if you need to supplement with protein powder, we recommend sticking with plant-based proteins. Whey isolate is okay. Plant-based and clear liquid drinks are also great options. Choose a protein shake that is high in protein 20 grams or more and low in sugar <5 grams.

Here are a few of our favorites. You can find them on Amazon.