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Diet Guidelines after Bariatric Surgery

Diet Guidelines after Bariatric Surgery

  • February 5, 2022


Bariatric surgery does indeed help with weight loss, but is it enough by itself? The answer to that question is obviously no. The success of weight loss surgery depends on various factors, including one’s diet. Patients who undergo bariatric surgery need to have a healthy, balanced diet that is both rich in nutrients and low in calories so that they don’t gain back too much weight. In fact, it is recommended to start the diet prior to the surgery; this will make the surgery and the weight loss procedure easier and more reliable.

Although patients are different from one another, the general diet process after bariatric surgery has identical stages among patients. What you need to know is that after your bariatric surgery, you can no longer eat as much food as you used to eat because your body cannot tolerate it. Furthermore, while your diet will be liquid-based in the initial stages after the surgery, your body will gradually become tolerant of different kinds of food – moving toward more solid foods over time. You will finally be able to eat normal food after three months. Your best advisor during this process is your surgeon, so don’t forget to keep them well-informed about your condition.

This post is for patients who have undergone Gastric Bypass, Gastric Sleeve, or Duodenal switch surgery.   

General Dietary Rules after Bariatric surgery

  • Eat and drink slowly.
  • You should chew your food thoroughly and meticulously. Every meal should take about 30 minutes.
  • You can only eat small amounts of food.
  • Patients usually start with six meals per day; then, when they start a more regular diet, they have three/four meals per day.
  • Avoid foods that contain high levels of sugar or fat.
  • Foods that are not easily chewed should not be part of your diet: bread, rice, tough meats, raw vegetables, and so on.
  • Drink 6-8 cups of water per day.
  • Avoid drinking during meals. There should be a 30-minute interval between a meal and your drinking liquids. 
  • Take mineral supplements and vitamins since the surgery makes it more difficult for the body to assimilate such nutrients.
  • Avoid alcohol, smoking, and don’t drink too much caffeine.

Bariatric Surgery Diet Stages

1. The clear liquid diet stage

Right after your surgery has been done, your clear liquid diet begins. In this stage, you should try to consume 64 ounces of clear fluids and 60-80 grams of protein every day.

  • Duration: This diet stage starts right after your surgery and lasts for a day or a few days.

The foods you can consume during this period include:

  • unsweetened fruit juices
  • broths
  • skim milk
  • decaf coffee and tea
  • sugar-free gelatin

We emphasize the word “clear” which signifies the fact that your body can only tolerate diluted drinks and juices, meaning that drinking thick fluids could cause complications. It is crucial to stay hydrated in this step and to drink enough water.

Moreover, this diet is very limited in calories, so your daily intake should be around 300 calories or less. Every meal should include ½ cup of liquids. During the first 1.5 months, because your stomach hasn’t fully healed yet, try not to drink fluids that are too cold or too hot as they may harm your body. Vomiting and nausea are common experiences during this period.

2. The full liquid diet stage

After a few days have passed, it’d be time for you to move on to the next stage of your diet. Full liquid foods are fluids that turn into liquid at room temperature. At this stage, you can have thicker fluids that are low in calories, high in protein, and don’t contain too much fat or sugar. You may feel full after having 1-2 tablespoons and that’s completely normal. Bear in mind that you should only eat until you are full and shouldn’t go over 400 calories per day.

  • Duration: This diet will continue until 2 weeks after your bariatric surgery.

Here are some food recommendations:

  • Sugar-free yogurt (without fat)
  • Cottage cheese containing little fat
  • Skim milk (without added sugar)
  • Oatmeal
  • Protein shakes (containing about 24 grams of protein)
  • Pureed soups
  • Instant breakfast drinks

You should start taking mineral supplements and vitamins 8 days after surgery. Remember, 64 ounces of liquids have to be consumed every day as well as 60-80 grams of protein, similar to the previous stage. Staying hydrated is important in every stage of your diet and this stage is no exception. Waking can help your digestion process during this period.

3. The pureed diet stage   

Now you can add pureed/mashed foods to your diet. Such foods have a smooth consistency, similar to a thick liquid; in addition, these foods should contain sufficient protein (at least 60-80 grams per day).

You can use a blender with some liquid (skim milk, low-calorie broth) to fully puree your food. Three to six meals can be eaten per day where every meal consists of 4-6 tablespoons and should take approximately 30 minutes. Staying hydrated is not to be forgotten (drink 6-8 glasses of water per day). Continue taking the mineral supplements and the vitamins. You should not drink for 30 minutes before or after a meal; otherwise, you’ll feel full really fast. Your calorie intake should not exceed 500 calories.

  • Duration: From the second week until the fourth.

Here’s a list of foods that fit the mentioned description:

  • Cottage cheese
  • Unsweetened applesauce
  • Noodles
  • Refried beans
  • Tofu
  • Mashed potatoes
  • Lean ground meats
  • Pureed vegetables
  • Pureed fruits
  • Scrambled eggs
  • Tuna fish
  • Avoid bread

4. The soft diet stage    

At this stage of your diet, you will finally get to experience chewing after so long. It is vital to chew thoroughly until the food has taken a consistent pureed form. The points we have mentioned many times by now: Stay hydrated, each meal should take 30 minutes, take your supplements and vitamins, and stop eating after you are full. The food that you eat has to be naturally soft, easily chewed, and rich in protein (at least 60-80 grams per day). Eat slowly and pause each time after you swallow to prevent your stomach from being overloaded.

  • Duration: From week four until week six

Here’s a list of foods we suggest:

  • Well-cooked vegetables
  • Fish
  • Low fat cheese
  • Fruit
  • Tender, well-cooked meat
  • Pasta
  • Dairy products (skim milk, yogurt)
  • Avoid bread, skins and seeds on fruits and vegetables

5. The solid food stage

You can now add solid foods with normal texture to your diet at this point. Consume ¾ cup of food every meal. The points we have mentioned many times by now: Stay hydrated, each meal should take 30 minutes, take your supplements and vitamins, stop eating after you are full, make sure to chew completely before swallowing, and consume 60-80 grams of protein every day.

  • Duration: Week six onwards

Although you can now eat solid foods, that doesn’t mean will be tolerant of any food without problems. Foods such as raw vegetables, tough meats, and bread can still cause problems. After some time, however, you will hopefully be able to add these to your diet if your doctor agrees, that is. Add foods to your diet one by one so that you can trace the effects and the results, so if a specific food causes nausea or vomiting, you can recognize it.

Long-term Diet Guidelines after Bariatric Surgery

Starting from the second month, you should plan your long-term diet and stick to it no matter what. Your diet has to consist of foods that are healthy, nutritious, and small in size without too many calories. Based on these criteria, decide what you should eat and what you should avoid. You will surely require lean protein, fruits, and vegetables in your diet, while you would have to cut down on fat and sugar as they can cause dumping syndrome.

Long-term Diet Details

Amount and Frequency of Food Intake

You should aim to consume 800-1000 calories a day from here onwards. You would naturally need to keep track of the number of calories you consume per day. Try to eat at least three meals per day and do not skip any meals as it could lead to serious hunger and overeating. Each meal is the size of ½ to 1 cup of food. If you can’t eat all the required food in one meal, divide them into different meals. Remember never to eat after you are full. If you wish to snack between meals, do it only once or twice a day; otherwise, your stomach will be full before you get the chance to have your meals.

Types of Food and Priorities

Furthermore, the foods you consume have to contain the necessary nutrients for your body; foods such as fish, lean meat, pork, fruits, vegetables, and low-fat dairy products can be considered of this type. Always start with the protein part of your food and then eat the rest. Consume lean foods and cook food through baking, boiling, grilling, and steaming. Fried foods should be avoided for several reasons: 1. they contain high levels of fat 2. they are hard to digest and could even cause dumping syndrome. Avoid white bread due to its low nutritional value and processed lunch meat because of its high levels of sodium. Whole grain bread has the same calories as white bread with more nutritional value including more proteins and fiber.

Stay Hydrated

Always stay hydrated and drink 8 glasses of water (2 liters) daily. Skim milk can be a good source of protein, and we recommend 8 ounces of it every day. Don’t drink 30 minutes before or after meals.


You will need to consider multivitamin, mineral supplements, calcium supplements, vitamin D supplements, vitamin B12 supplements, and even iron supplements (especially in women) as a part of your diet now and forever.

What to avoid

  • Avoid empty calories that offer no valuable nutrients.
  • Avoid smoking and alcohol. Alcohol should be avoided at least for six months after surgery.
  • Avoid processed meats and fried foods.
  • Bariatric surgery patients should cut down on sugar and fat.
  • Do not eat or chew fast.
  • Do not overeat.
  • Your body can tell you what you’re tolerant of and what you are not. In other words, your body can guide you through the process of planning your diet.


  • Protein is vital in the diet of a bariatric surgery patient. What are some foods that contain protein?
    • Chicken
    • Skim milk
    • Fish and seafood
    • Low-fat cottage cheese
    • Tofu
    • Fish
  • How important is it to stay hydrated?
    • The reason we stress staying hydrated so much is that it helps the body dispose of waste. This is crucial because after your surgery, you will have lots of waste that need to be removed. In addition, water helps you eat less by taking up space in the stomach.
  • What does dumping syndrome mean?
    • Having foods with too many particles (sugars, for example) on an empty stomach makes you lose blood volume due to the water in your body being used for the dilution of said particles. You will feel cramps, turn pale and start to sweat. Diarrhea may also follow. Bottom line is don’t eat such foods on an empty stomach.   
  • Why is having red meat bad?
    • Red meat is hard to chew, and, consequently, difficult to digest. Second, its cartilage may block the pathway in your stomach.
  • Is it bad to eat salt bad after having bariatric surgery?
    • It’d be best to avoid salt as much as you can during the first weeks after your surgery. However, having 1500mg of salt per day will not cause any harm. Bear in mind that although sodium doesn’t contain calories, salty foods are often high in calories. Overall, you shouldn’t be too concerned about sodium, but try not to consume too much of it.
  • Can I snack between meals?
    • Most doctors would say no and the ones who do say yes would only allow it if it is done once or twice a day. If you desire to snack between meals, make sure to only eat snacks that are beneficial, not ones that just fill up your stomach and offer empty calories.

Here’s a list of some healthy snacks:

  • Beans
  • Yogurt
  • Cottage cheese
  • Eggs
  • Nuts (not too much because they could be hard to digest)
  • Fruits including apples, oranges, carrots, grapes, melon and cherries
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