The Pre-Op Diet

Bienvenido’s to
Elias Ortiz and Company!

We welcome you into our circle of friends and family. We promise that we will help support you along every step of your journey.  With preparing for the pre -op diet, we believe in keeping it SIMPLE.

The pre op diet is designed to help you prepare for your surgery in several ways:
  • Physically it helps to clean out the stored glycogen from the liver which helps to shrink and make the liver less inflamed. It does help to reduce intra-abdominal belly fat .
  • Mentally it will help you adjust to eating smaller portions, and eating a lean, green and clean diet unprocessed foods. 


Length of diet

BMI 30 TO 32 – 1 WEEK PRE-OP

BMI 33 TO 50 – 2 WEEK PRE-OP

BMI 51 TO 60 – 3 WEEK PRE-OP

BMI 61 TO 70 – 5 WEEK PRE-OP


Protein shakes

You should have two to three protein shakes a day. See our recommended protein powder.

You can make homemade shakes with lite soy, lite rice, lite almond, lite cashew milks etc.

EACH protein shake should be the following:

  • Not be more than 250 calories total
  • Have at least 15 grams of proteins
  • The carbohydrates should not be more than half that of the number of grams of proteins. 

Suggested protein powders:

There are 100 brands that meet the doctor’s recommendations including:  

  • Apples and Pears (formulated specifically for bariatric patients)
  • Atkins
  • Premier Protein
  • Clean Protein by Orgain
  • Vega Plant based
  • Slim Fast
  • Walmart Generic Protein shakes
  • GNC Lean Shakes
  • Fit
  • Quest
  • 310 protein shakes
  • Inspire

Approved drinks on the pre-op diet:

  • Water
  • Black tea
  • Coffee (caffeine is OK)
  • Organic coconut water without the bits and pieces or infused waters. Do not eat the fruits out of the infused waters. 

Remember actual fruit is not allowed on the pre op diet, only the juices and infused waters during the clear liquid part of the prep.  Drink up the water as much as you would like!  

To flavor your water, but do not eat them, you can add a combination of any of the vegetables from the non-starchy vegetable list plus fresh mint, cilantro or cinnamon to any of these fruit and vegetable infused waters! And for a touch of sweetness, you can use stevia or monk fruit.

Infused water ideas

  • Water + Cucumber + lemon slices  
  • Water + red berries + lemon slices 
  • Water + watermelon + cantaloupe  
  • Water + pineapple + orange slices  
  • Water + apples +pears  

Fresh Juices

This can be made in a juicer or in a blender and strain avoid vegetables and fruits that contain pulp remember the fruit juices are for the clear liquid days any infused waters and the vegetable juices are for the whole pre op diet including the clear liquid days. No fruit juice or pieces of fruit during the regular preop diet are allowed. 


For a little variety you can freeze your infused water or juices to make tasty popsicles. 


Simply mix the infusions with unflavored gelatin. 

Notes about cooking oils and seasonings

You can use no calorie cooking spray to cook your meat and veggies but no butter or oils.

You can use dry seasonings to flavors your meat and veggies but fresh is always better and healthier.

Lean protein

Every day you will need 6 oz of lean protein for women and 8 oz of lean protein for men. The weight is measured raw, not cooked.

Lean proteins:

    • 2 eggs are equal 3 oz. of a lean protein.
    • Chicken, turkey, white fish, salmon, tofu, shrimp, scallops, crab, eggs, Egg Beaters, and very lean red meat.
    • Important: Only baked, boiled, roasted, grilled, nothing fried but you can use an air fryer!

For people that do not eat lean proteins or meats you may substitute plant based only if it’s 100% natural and organic but this is only for our vegetarians. You can substitute ½ cup of cooked beans for two ounces of your daily allowed lean proteins.


You can have unlimited non starchy vegetables.

Non-starchy vegetables include:

  • Broccoli, cauliflower, carrots, zucchini, green onions, white or yellow onions, cucumbers, bell peppers, tomatoes, celery, radishes, spinaches, ALL lettuces, alfalfa sprouts, turnip, collard, mustard greens, cabbage, asparagus, turnips, leeks, brussels sprouts, mushrooms, spaghetti squash. 

Vinaigrette dressing

 You can only have 2 oz per day of homemade vinaigrette dressing.

To make a simple vinaigrette dressing combine the following:

  • ½ cup – oil (olive, peanut, avocado, grapeseed) 
  • ¼ cup – fresh citrus juice or vinegar (balsamic, apple cider, rice) 
  • Add ingredients to flavor – honey, dijon mustard, ginger, garlic, herbs.

Important: no store bought dressings are allowed


Unlimited of the following allowed soups:

Clear liquid diet

Three days before surgery (include your surgery day in the count) you will be on clear liquids only. You will also need to take a laxative as well. See the clear liquid diet for more info on approved clear liquids.

For endoscopic sleeve gastroplasty patients you will have a slightly different prep. You will have only 24 hours of the clear liquid phase and 8 hours of fasting before surgery.


Laxatives can be any brand that you chose, and it is ok to repeat the dose one time but remember that laxatives can take up to 24-48 hours to kick in.

Pre-op Timeline

  • Two weeks before your surgery: if you are a smoker, you will need to stop!! Continuing to smoke close to your surgery date and not following the doctor’s recommendations may increase post-surgery complications and slow down the healing process.  For help and ideas on how to stop smoking go to the Center for Disease Control at: You are NOT allowed to use the E-Cigs, Vapes, but you can use the Nicorette Gum and patches but please stop gum and  patches 24 hours before surgery.   
  • Seven days before surgery: STOP ALL vitamins, supplements, fish oils, ginkoba, NSAIDS (non-steroidal anti-inflammatory) including Motrin, Advil, Aleve, Diclofenac, and Ibuprofen, you must stop any aspirin and arthritis medications because they can interfere with the blood clotting process. For general aches and pains, headaches you can use Tylenol, Extra Strength Tylenol and prescription pain medications that are not NSAIDS. If you take any blood thinning products or anticoagulants, please email the nurse directly for instructions. 
  • Three days before surgery: Stop any statins or cholesterol and diabetes medications. For all people with diabetes continue to check and monitor your blood glucose levels and treat accordingly. Please continue any heart, blood pressure, thyroid, anti-depressants, anxiety medications as directed. Take a good laxative, any brand that you chose, and it is ok to repeat the dose one time but remember that laxatives can take up to 24-48 hours to kick in. Remember that surgery day counts as the third day of clear liquids.
  • Travel Day:/ One Day Before Surgery: Continue with the clear liquid diet as directed.  You can take any blood pressure, heart, thyroid, anti-depressants, anxiety medications the morning of surgery with a small sip of water. No pain medications at this point. 

Health Disclaimer: This website provides information about health and related subjects. The information provided on this site, or in any linked materials, is for informational purposes only and is not a substitue for receiving direct professional medical expertise and / or treatment. If you think you have a medical emergency, call your doctor or emergency services immediately. 

Recipe & Food Disclaimer: We are not responsible for any outcome of any recipe you try from the website. Take care when using cookware including knives and other sharp or hot objects. Review all ingredients prior to ingesting to ensure you are not allergic to anything in the recipes. We do not provide any assurances or accept liability in regards to quality, nutritional value or safety when using the recipes provided on this site. 

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