Bariatric Surgery Diet Dos and Don’ts before and after the Operation

Chapter 4

Bariatric Surgery Diet

Our journey is coming to an end. After these final chapters, your information will be enough to make a life-changing decision on whether to go for a weight loss surgery or not. But before jumping to the next chapter, weight loss surgery diet before and after the operation, let’s take a short quiz. Just see how many of the below questions you can answer. Are you ready?

1- Why do overweight or obese patients choose bariatric surgery?

2- What are the preoperative weight loss requirements?

3- What are the most popular types of this operation?

4- What is the average weight loss after each surgery?

5- What changes should you make in your lifestyle before and after the surgery?

6- How much is the cost of different procedures?

7- What are the long-term and short-term post-surgery risks?

8- How can you reduce the risks of surgery?

Well, what’s your score? If you couldn’t answer all of them, make sure to take another look at the previous chapters. You don’t want to miss even one piece of information! In case you have given the right answer to question number 5, you must know how to follow a healthy diet and its necessity. In this chapter, we’ll cover all the eating tips you should be aware of weeks before the surgery, and also the ones you need to follow during specific periods after your surgery in order to have healthy nutritional management. Please note that these suggestions might not be beneficial for everyone, even though the main principles are mostly the same. So, make sure to consult with your doctor about your diet before and after the surgery.

Pre-Operative Weight Loss Diet

Pre-op diet both prepares you mentally for the post-op process and prepares you physically for the surgery by decreasing the complication risks. This diet is also known as liver-shrinking diet. A fatty liver makes the surgery hard for the surgeon, so they ask you to shrink your liver by doing a pre-operative diet.

Basically, this diet is high in protein and low in carbs. In this way, the body preserves the muscles and shrinks the fat cells at the first stage. Then, the fat cells are filled with water because the body doesn’t want to lose its emergency fuel. But when the water is also emptied from the cells, the fat amount decreases around the liver.

Why pre-op diet?

In order to decrease the possibility of different risks of complications, you need to follow a set of instructions to reduce the size of your liver during the preoperative period. Even a modest weight loss may increase the success rate of surgery. However, your doctor is in charge of identifying the need for pre-op weight loss. So, in case they advise you to go on a specific diet during a particular time before your surgery, you must stick to this diet and follow it word by word, otherwise, you will put yourself at high risk, and even there’s a chance your doctor cancels your surgery.

Why Do Some Surgeons Require Pre-op Diet for Gastric Sleeve and Others Don’t?

Those who suggest pre-op diet hide behind the fact that body fat alters the organ, and when correlated with anesthesia, the organs are affected much more badly. So, before surgery, they aim to decrease the fat for patients to have a lower BMI.

Some other surgeons, on the other hand, defend that as long as the patient’s BMI is not greater than 50, there is no point in following a diet plan. Before deciding to have the surgery, these patients already try dieting, exercising, detoxing and basically, they have enough of it. As the last chance to lose weight, they consider bariatric surgery. Especially, gastric sleeve mortality rate is lower than %1. That’s why, surgeons do not want to bother their patients, as the diet is not going to affect their well-beings after the surgery.

Who is it for?

Patients whose BMI is equal to or greater than 50 have higher complication risks during and after the surgery. Obese patients do not suffer not only from obesity but also other metabolic and cardiovascular diseases or syndromes. Regarding these conditions, you may be obliged to do a diet to minimize complication risks. It is illegal to operate on a patient whose BMI is equal to or greater than 63. These patients will be on a diet until their surgeons do not see the surgery is risky for the patient.

What to Eat

If your surgeon or dietitian recommended you a pre-op diet, here is an idea to what to consume. Protein shakes, and other high-protein, easy-to-digest food will be the most part of your pre-op diet. Protein is necessary for muscle tissue protection. As a consequence, during the weight loss process, you will lose fat, not muscles. Here’s a sample diet you can follow 2 to 3 days a week. You can ask your doctor for more eating plans.

Breakfast 2 boiled eggs, 200 ml protein shake (unsweetened), 5 olives and unlimited seasonal greens
Lunch 120 gr lean meat/chicken/fish, boiled vegetables
Snack 1 portion fresh fruit
Dinner 120 gr lean meat/chicken/fish, boiled vegetables, non-fat yogurt and seasonal salad
Snack 10-12 raw almonds

During the day, do not forget to drink approximately 85 oz of water; you should keep yourself hydrated. As much as you consume water, the weight loss process will be so much faster.

Approximately 2 days before the surgery, you need to transition to a mostly liquid or all-liquid diet. But the final decision is made by your doctor. Please, do not eat anything out of their prescriptions. Also, make sure to ask your anesthesiologist about the food and drinks you can or can’t have before the surgery.

Other Foods and Drinks to Consume During the Pre-op Diet

  • Protein shakes
  • Sugar-free drinks
  • Drinks without caffeine
  • Soup broth
  • Vegetable juice

If your surgeon approves, you can consume one to two daily servings of lean meat or vegetables.

Exercise Before Weight Loss Surgery

Don’t assume your excess weight loss journey starts after the operation, but it begins the exact moment you decide to undergo surgery. As the famous aphorism suggests, fake it till you make it. You should start to insert the post-surgery changes into your life, even before the actual surgery day. You don’t need to become a pro in such a short time. Even a 10-min walk every day is much better than nothing. Imagine yourself with your ideal body weight. This is the strongest motivation that will keep you moving before the surgery and even long after that.

Post-Operative Weight Loss Diet

A post-surgery diet consists of 4 phases, each of which helps your body to heal and accelerate long-term weight loss. We’ll go through each of them in the following sections. But before we take a closer look at each phase, let’s see what we mean when we say ounce, cups, teaspoon, and other portion measurements.

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Phase 1 of the Post-Op Diet: Clear Liquid Diet

This stage starts immediately after your surgery, from your hospital stay, and after your discharge. Its duration is usually different for gastric bypass surgery, sleeve gastrectomy, gastric bypass with duodenal switch, and lap band patients: Gastric sleeve and gastric bypass patients ==> Weeks 1 and 2 Lap band patients ==> Week 1 Attention! Stay hydrated. That’s the first and foremost rule of this period.

Diet Guidelines to Keep Well Hydrated

  • Keep drinking liquids

You have to sip 48–64 ounces of fluids every day, which is on average, seven 8-ounce cups of drinks.

  • Stay away from fruit juices

Overall, fruit juices are perfect for bariatric patients, but in the beginning, due to the possibility of nausea or diarrhea, you’d better avoid them.

  • Not too hot, not too cold

Extremely hot or cold drinks may cause discomfort as your stomach is not completely healed yet. After maybe the 6th week, you can start to drink hot or cold fluids. Remember, your stomach is still recovering from bariatric surgery. It’s common to experience nausea or vomiting at this point. Please keep yourself hydrated.

More Options for a Clear Liquid Diet

Fruit Juices Broths Other Drinks
  • Apple
  • Grape
  • Cranberry
  • Clear beef
  • Chicken
  • Vegetable
  • Water
  • Ice chips
  • Coffee or tea with no caffeine
  • Low-calorie sports drinks

After visiting your surgeon, they will tell you if you’re ready to move to the next stage. So, this phase might become less or more based on your doctor’s diagnosis. However, it usually takes two weeks for most bariatric patients.

Phase 1/B, for Gastric Banding Patients: Full Liquid Diet

This phase is mainly for gastric banding patients and it usually starts from the end of week one and lasts for about a week.

What to Eat During the Second Week After Laparoscopic Adjustable Gastric Band

Keep drinking 48–64 ounces of fluids per day. Add more fluids to your diet:

Beverages Protein Supplements Other Drinks
  • Liquid replacements for solid food
  • Skim milk with protein powder
Protein supplements after each meal Non-fat yogurt

Remember, nausea and vomiting are normal after gastric banding because your body is still recovering. Just stay hydrated and you’ll fully recover soon.

Phase 2 of Post-Surgery Diet: Pureed Foods

(Weeks 3 and 4) After a thorough examination, your surgeon will ask you to proceed to the next phase, which requires pureeing your food. Patients should mostly start this stage 3 weeks after surgery and follow this diet for about two weeks. Main goals of pureed food diet are:

  • Provide more variety, nutrients, and fiber
  • Include high-protein food in the post-surgery diet
  • Taking chewable vitamin supplements with minerals

Gastric bypass patients should take their protein supplements after each meal. Protein matters so much in your post-surgery life that we’ve devoted one part of this article to it. You’ll read more about its significance later. Laparoscopic adjustable gastric band patients can take the required protein supplements just as they did in the first stage.

Points to Remember Regarding Drinking Liquids

  • At least 30 minutes after each meal is the best time to consume protein supplements or protein shakes (8 ounces) in addition to sugar-free liquids.
  • Do not drink too much drinks at once and then non for 5 or more hours. There should be 3-hour intervals between drinking liquids.
  • Do not drink any fluids, including water, for at least 30 minutes before and after your meal.

Pureed Food Ideas

Proteins Vegetables Fruits Grains
  • Sugar-free, zero or low-fat yogurt
  • Strained cream soups (celery, potato, mushroom, or chicken made with skim milk)
  • Skim milk with half a scoop of protein powder
  • Low or no-fat cottage cheese
  • low or no-fat Ricotta cheese
  • Scrambled eggs or egg substitute
  • Beef, chicken, or turkey
  • Whitefish (cod, haddock, orange roughy)
  • Canned chicken breast
  • Canned tuna fish in water
  • Tomato juice
  • Diet V-8 Splash® or V-8 Juice®
  • High-protein vegetables like spinach, carrots, and green beans
  • 100% fruit juices (apple, grape, cranberry)
  • Light juices sweetened with non-nutritive sweetener (aspartame, acesulfame, and potassium)
  • Applesauce
  • Bananas or canned fruits in their own juices
  • Peaches, apricots, pears, pineapples, and melons
  • Cream of wheat or cream of rice
  • Farina
  • Grits
  • Mashed potatoes/sweet potatoes
  • Winter squash

The non-fluid items of the above-mentioned table must be mashed and pureed. Remember that because this is a pureed food phase, not even soft food is allowed yet. You don’t know how to puree food? Read the next part then.

How to Puree Foods

1- After cutting boiled food into small pieces, put them in a blender or any kind of food processor. 2- Add some liquid to it. You can use skim milk in this phase as the liquid of your pureed food. Both are also a good option. 3- Puree your food until it gets totally smooth. Your pureed food, as soft as baby food, is ready to be eaten!

Phase 3 of Post-Op Diet: Adaptive/soft Diet

* Months 2 and 3 for Gastric Sleeve and Gastric Bypass Patients * Weeks 5 and 6 for Gastric Banding Patients

Now your stomach is fairly healed and ready to digest soft, solid pieces of food. So, you can add fish, cooked vegetables, meat, chicken, and other soft foods to your diet. It is necessary for women to use about 50 grams of protein and for men to use 60 grams of protein on a daily basis. You can first eat high-protein food, and then continue with the rest of your meal, so in case you become full up, your body has received the necessary amount of protein. Don’t forget your daily chewable vitamin supplements and of course, drink plenty of water and fluids.

Food to Avoid

Foods to Avoid During Phase 3 of Post-Op Diet
  • Raw vegetables
  • Skins and seeds on fruits and vegetables
  • Bread
  • Fatty food
  • Fried foods like chips

Phase 4 of Diet After Weight Loss Surgery: Stabilization Diet

The last phase of your post-surgery diet begins at some point between months 4 and 6 after the operation and usually takes more than months after surgery. If your doctor is sure your body is ready for this phase, they will ask you to start eating food with more normal consistency. However, you can’t ever go back to your eating habits and regular diet before surgery. It is better to follow this diet until you get the healthy weight you had in mind before surgery. Rapid weight loss enables you to pass this stage faster.

Points to Remember During Phase 4 of Post-Op Diet

  • Do not miss any of your three meals a day.
  • Make sure to keep your daily meals well-balanced.
  • Have drinks with 0 calories during the day, but not with your meals.
  • Pay attention to eat rich in nutritious foods. So, your pieces of food intake must be all nutrient-dense to avoid malnutrition.
  • Steer clear of fatty or sugary food with no protein, minerals, or vitamins.
  • Stay with your vitamin supplement with minerals.
  • If the amount of food your body can tolerate is not enough, you can divide your three meals into 6 parts and eat more than 3 times a day.
  • Stay away from liquids less than 30 minutes from your meals.

What to Eat During Phase 4 of Post-Op Diet

Proteins Vegetables Fruits Grain
  • Different types of fish and shellfish
  • Chopped Turkey breast
  • Chopped chicken breast
  • Low-fat cheese (sliced)
  • Boiled eggs (mostly egg whites)
  • Poached eggs
  • Soups with skim milk
  • Cooked vegetables
  • Canned vegetables
  • Canned fruit
  • Soft fruit without skin (bananas, apples, peaches, pears
  • Sugar-free porridge
  • No sugar cereals (with skim milk)
  • Baked potatoes (sweet or normal)
  • Pasta, noodles, or white rice (boiled)

Food to Avoid

You should not consume hard-to-digest food at all, otherwise, you will feel a lot of discomforts:

  • Fatty foods such as fast food, burgers, chips, fried food, etc.
  • Popcorn
  • Dried fruit
  • Bread
  • Muffins
  • Carbonated beverages
  • Crunchy foods
  • Spicy foods
  • Junk food
  • Alcoholic beverages

More Tips on Post-Surgery Eating Habits

1- Your dietary intake is different from your food intake before weight-loss operation. The picture below clearly shows how your plate should look like after weight loss surgery.

2- From now on, everything in your life should change. You don’t want to consume unhealthy food anymore. So, the first step is to stop buying them. Fill your fridge with healthy nutrients and welcome them to your life.

How to Reduce Post-Op Risks through Healthy Eating Habits

Surgery makes major changes in your body and in case you do not take care of your health, you will face uncomfortable surgical complications. Systematic review shows patients can eliminate a lot of these risks with new healthy eating habits they adopt. A healthy diet even reduces the possibility of mortality in patients to some extent.

Risks Solution
Dumping Syndrome
  • Drink 64 ounces of liquids, including water, per day
  • Do not drink liquids with meals
  • Do not consume too many simple carbohydrates (pasta, rice, and potatoes)
  • Drink a lot of water and other healthy, sugar-free liquids every day
  • Eat rich in fiber foods
  • Exercise on a daily basis
  • Eat more slowly
  • Drink a lot of fluids
Lactose Intolerance
  • Drink lactose-free fluids
  • After consulting with your doctor, take lactate enzyme tablets
  • Do not drink too cold fluids
  • Avoid or limit consumption of fatty or gassy foods
  • Your last meal should be at least two hours before going to bed
Blockage of the opening of the stomach pouch
  • Chew your meals a lot, carefully, and slowly
  • Moving to the next phase of your diet without consulting with both your surgeon and dietitian is not recommended at all and may cause stretching of your stomach.
  • Slowly move from one phase to another.


Protein Is Important

During your weight loss process, what you want to lose is the fat stored in your body, not your muscle mass. To protect your muscle mass and have enough energy to do your daily tasks, you need to increase the amount of your protein intake. It also prevents thin hair and weak nails. But the only way to get that protein to your muscles and strengthen them is to eat 60 to 80 grams of protein per day. Moreover, medical evidence proves more muscles prevent saggy or excess skin after weight loss surgery. Protein shakes are good sources of protein both before and after the surgery. Here’s the anatomy of your protein smoothies:

You can choose different ingredients for your protein shake from the foods and drinks we mentioned in this article. But still, it’d be better to check with your doctor as well. Also, here’s a list of ideas you can use for your post or pre-bariatric surgery protein smoothies.

Eating which types of food is your most favourite? Which restriction is the most difficult one for you? Well, are you ready for the last chapters? So, let’s move on to our guide on the costs of all bariatric surgeries and the factors that influence these prices.

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