Gastric Sleeve Pre Op Diet

By removing a portion of the stomach, gastric sleeve surgery aims to create a thinner area for food to be stored. As the stomach is made smaller, it doesn’t take as much food to become full and therefore it becomes easier to lose weight. In essence, the surgery has been created to help you lose weight but you still may be asked to follow a specialised gastric sleeve pre op diet beforehand.

Goals - If you are placed onto a pre-op diet, there are two main goals - reduce the size of the liver and remove body fat. For the first, the reason is self-explanatory in that the surgery becomes a lot safer if the liver is smaller. In terms of removing body fat, this also helps the liver because it reduces the likelihood of something going wrong such as a puncture in the liver during surgery.

Guidelines - When you meet with your physician, they will give you some simple guidelines to follow before your surgery. Firstly, most cases will see the diet last for two weeks and calorie intake should drop to around 1,000 to 1,200 per day. On the whole, solid foods will be out whilst protein shakes and other supplements are used in their place. One of the dangers of a diet of this type is the amount of water than can be lost so, as a result, around six to eight glasses of water is advised. If not water, a low calorie sugar-free alternative.

Importance of Protein - During the two weeks, you will need to utilise a high-protein diet whilst cutting carbohydrates down significantly. When our bodies are short on carbs, they start to find energy from glycogen stores which helps with water and weight loss. In order to feel full and allow the tissue to repair at an efficient rate, you will need to consume between 80 and 120 grams of protein with the main source coming from drinks. Although there are many options on the market, many believe whey protein isolate to be the best as it has a high absorption rate. When it comes to milk, the powder should be mixed with water or skimmed milk rather than full-fat. If you are lactose intolerant, soy milk provides a good alternative.

Warning - At all times, it is important to remember that gastric sleeve surgery is a lifestyle commitment as opposed to just having your hair trimmed. The temptation to consume high fat foods will be high but you must follow all recommendations from physicians so that you can be in the best possible position going into the surgery. In many cases, patients have been rejected for not losing enough weight prior to the surgery date so this two week diet is essential.

Gastric Sleeve Pre Op Diet Guidelines

Protein powder/drinks 

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 half the grams or less than protein- if you have 20 grams of protein, it should have less than 10 grams of sugar

General Overview – Gastric Sleeve Pre Op Diet (2 Weeks Prior To Surgery)

  1. 2 – 3 protein shakes per day
  2. You can eat as many raw or cooked vegetables as you want 
  3. 2 servings of 4 oz. of a lean protein (chicken, turkey, fish, lean ground beef, eggs, tofu, beans of any kind except baked or BBQ beans. (you can have more than 4 oz.; this is the minimum per serving)
  4. 1 – 2 servings of a healthy fat (salad dressing, olive oil, nuts, avocado, olives)
  5. You can make your shake with unsweetened vanilla almond milk or coconut milk (no regular milk- too much sugar)
  6. Absolutely NO bread, rice, pasta, potatoes, sweet potatoes, yams, cereals, oatmeal, popcorn, refined grains, corn, peas, sauces with sugar

Approved Liquids:

Apple or other clear juice without pulp or carbonation.

Clear broths: Chicken, Vegetable, or Beef.  You may at this time drink other drinks as long as they have NO SUGAR.

7 Days Prior to Surgery – Gastric Sleeve Pre Op Diet

  • Some medications may need to be discontinued before surgery depending on the instructions of your physician.
  • Specific medications to discontinue: Coumadin, Plavix, Aspirin, Ibuprofen, Motrin, Advil, Nuprin, Aleve or any other non-steroidal anti-inflammatory medication. **Remember this also includes baby aspirin and most arthritis medications. As these can all cause stomach irritation and possibly more bleeding post operatively.
  • Discontinue birth control and supplemental hormones
  • Discontinue Vitamin E
  • For headache or minor pains you may use Tylenol.
  • Do not take any herbal medications/remedies.

2 Days Prior to Surgery-Begin Clear Liquid Diet – Gastric Sleeve Pre Op Diet 

  • Consume only clear liquids:
  • Water or Flavored Water.
  • Need to have 2 Greek yogurts per day (may be flavored but no pieces of fruit) – this helps with post healing and providing healthy bacteria in your gut. Plain Greek yogurt is your best option or something similar. 


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