Before Gastric Sleeve Surgery

We will schedule an appointment with your surgeon for your pre-operative appointment within 30 days before your procedure to answer any questions you may have.

Your pre-operative diet begins two weeks prior to surgery.

Include your bariatric multivitamin and calcium during this phase. The day before surgery you must only consume liquids. Do not eat any solid food the day before surgery.


  • Consume a minimum of 64 ounces of water per day. Other fluids can also be included as long as they are: 
  • Uncarbonated
  • Sugar-free
  • Caffeine-free (examples: Crystal Light, Powerade Zero, decaf unsweet tea)
  • Drink two high-protein, low-carbohydrate shakes per day.
  • Shakes should be limited to 10 grams of carbs or less per serving.
  • Shakes should have at least 20 grams of protein per serving.
  • Wean off caffeine-containing drinks over these two weeks. You will need to avoid caffeine for the first two weeks after surgery (until the Soft Food Diet stage starts).


  • Eat one meal per day. Follow the Pre-Op Diet meal guide below.
  • Eat 1-2 snacks per day. Limit to no more than 10g of carbs per snack (example:½ cup fresh berries, ¼ cup nuts, or string cheese with 2-3 crackers).

Purpose of the pre-operative diet:

  • Reduces the size of the liver, which lies over the upper stomach.
  • Reduces abdominal fat, making access to the stomach safer and easier.
  • Thins out the wall of the stomach, making the stapling portion easier.
  • All of this adds up to an easier and safer surgery, and results in a tighter sleeve for you!

Pre-Op Diet Meals (one per day)

Pick a 4-6 oz protein, add up to ½ cup of starchy vegetables, and fill in with unlimited non-starchy vegetables.

Pick a lean protein (4–6 oz)




2-3 large eggs

¾ cup liquid egg whites

93/7 ground meat

Venison (deer)

Extra firm tofu

Add a starchy vegetable (up to ½ cup)


Sweet potatoes


Beans (not BBQ-style)


Add non-starchy vegetables (unlimited)


Leafy greens (spinach, lettuce, kale)

Green Beans









Brussels sprouts

Squash / zucchini




Protein Shakes (two per day)

Protein shakes should be low carbohydrate (10g carbs or less) and should provide at least 20 grams of protein per serving.Options may include ready-to-drink bottles or powders that mix with water to make a shake. Here are a few options to consider:

Premier Protein®

Milk-based protein, lactose free
30 grams of protein per serving; 4-6 grams of carbohydrates per serving

Pure Protein® 100% Whey Protein Powder or Shakes

Whey Protein/Milk Protein Isolate
30 grams of protein per serving; 6 grams of carbohydrates per serving

Fairlife® Nutrition Plan

Milk-based protein, lactose free
30 grams of protein per serving; 3-4 grams of carbohydrates per serving

Muscle Milk® (various options)

Milk-based protein
20-40 grams of protein per serving; 7 grams of carbohydrates per serving

Vital Proteins® Collagen Peptides

Unflavored: 20 grams of protein per serving; 0 grams of carbohydrates
Chocolate: 20 grams of protein per serving; 4 grams of carbohydrates

Sample Meal Plan

Provides less than 900 calories and 75-95 grams of protein. Does not include your water goal of 64 ounces or more per day. 


Protein Shake


Celery with 1 Tbsp peanut butter, string cheese with ½ cup fresh berries


4-6 oz grilled chicken breast, ½ cup baked sweet potato, small salad of spinach, tomatoes and shredded carrots with light drizzle of infused olive oil dressing (~2tsp)


Protein Shake

Medication changes before surgery

Talk with your doctor about how to adjust medications, including insulin, during this low calorie, low carbohydrate diet phase.

  • Smoking, vaping, dipping chewing tobacco or any form of nicotine are strictly prohibited, due to the increased risks of surgical complications. You will undergo nicotine testing for confirmation before surgery will be scheduled.  You will be required to commit to avoid nicotine completely after surgery as well, due to the increased risks of stomach ulcers.
  • Discontinue all hormonal therapy (testosterone, birth control pills) one month before surgery to reduce the risk of blood clots. If you have implantable birth control or an IUD, you do not have to have this removed. Thyroid medication should continue to be taken.
  • Discontinue phentermine, Ozempic®, or any other diet medication 2 weeks before surgery due to potential interactions with anesthesia.
  • Discontinue all herbal supplements other than vitamins two weeks before surgery.
  • Start bariatric vitamins at least two weeks before surgery. You may be prescribed vitamin supplements earlier if deficiencies are identified in your blood work.
  • Discontinue aspirin, all products containing aspirin (Excedrin®, Goody’s® powder, BC® powder, etc.), and all nonsteroidal anti-inflammatories (ibuprofen, Advil®, Motrin®, Aleve®, naproxen, diclofenac, meloxicam, etc.) 1 week before surgery to reduce the risk of bleeding.
  • If you are taking a blood thinner, you may be asked to stop taking it leading up to your surgery depending on why you’re taking it.
  • Instructions regarding other medications will be made at your pre-op or pre-admission testing appointment.

Please contact us if you have any questions regarding your medications or pre-op diet instructions.

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