Duodenal Switch Surgery Pre-Operative Diet Guide

This nutrition guide aims to help shrink your liver before the duodenal switch surgery (DS) by depleting stored glycogen. The regimen applies to both classical biliopancreatic diversion (BPD-DS) and its variation loop duodenal switch (SADi-S). The goal is to consume 2-3 meals of solid, macronutrient-rich foods daily. These whole meals will stay in your stomach longer, keeping you full while providing your body with vital nutrients. In addition, utilize protein shakes as a snack; generally, 1-2 protein shakes per day. This will ensure you meet protein goals, which will promote wound healing during your post-op recovery. 

Pre-Surgery Diet Guidelines Based on BMI

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

  • 30-32 =  2 days clear liquids only

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

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

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

  • 50-59 = 6 weeks of pre-op diet including two days of clear liquid diet

  • 60 plus = 8 weeks pre-op diet including two days of clear liquid

Bariatric Surgery Pre-Op Diet Guidelines Based on BMI

General Overview

  • 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, or peas)

  • 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 add ½ cup of frozen berries or ½ banana to your protein shake

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

  • NO bread, rice, pasta, refined grains, tortillas, sauces with sugar, and no dairy (milk, yogurt, cheese)

  • 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.

Behavior/Lifestyle Changes

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

  • Discontinue drinking ALL caffeine 2 weeks prior to your surgery date. Caffeine is a diuretic, which is acidic and may cause dehydration. 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 after Duodenal Switch surgery.

14 Days Prior to Duodenal Switch Surgery

  • 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).

7 Days Prior to Duodenal Switch 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 Duodenal Switch Surgery – Begin Clear Liquid Diet

  • Consume only clear liquids: Apple or other clear juice without pulp or carbonation. (Honest Kids Juice is the lowest in sugar (10 g. per serving. If you get regular juice use 100% real juice and dilute 60/40 with water)

  • Clear broths: Chicken, Vegetable, or Beef.

  • Water or Flavored Water.

  • Sugar-free drinks such as crystal light, vitamin zero water, Powerade zero.

  • Sugar-free popsicles and sugar free jello (any color is acceptable)

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.

Diet Preparation Guidelines

Here is a sample meal plan to help you prepare for the DS surgery.

Here 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: 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

Approved Proteins and Vegetables

Grass-Fed MeatCelery
LambBok Choy
90/10 Lean cut beefMushrooms
Lean pork
(Pork Tenderloin)
Wild Game
(Buffalo, Elk, Venison)
Organic PoultryAsparagus
Chicken BreastTomato
Eggs / Egg WhitesCauliflower
Egg SubstituteBell Pepper
Wild Caught SeafoodEggplant
ClamsBrussel Sprouts
LobsterGreen Beans
ScallopsBlack Beans
Protein AlternativesChickpeas
Vegan Protein PowderSpinach
Whey Protein PowderCucumber
Nuts & SeedsOnion
Beans (all varieties)Lettuce
Impossible Burger
Fairlife Milk

Approved Fats

Healthy Fats 

  • Avocado
  • Olive Oil
  • Nuts (Limit to a handful per serving)
  • Nut Butters (1 TBSP per serving)
  • Chia Seeds
  • Flax Seeds
  • Hemp Seeds

Recommended Protein Powders

Whey isolate and plant-based proteins are recommended. 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.

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