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Gastric Bypass Diet 


Immediately after your gastric bypass surgery you need to allow time for your internal stitches to heal properly and the swelling to calm down. Your digestive system will gradually adjust to a new diet that you will now be eating. Recovery will vary from patient to patient but it can take three to six months for your body to settle totally.

Initially post-op your diet will be limited to liquids for the first two weeks, starting with clear fluids and moving on to full liquids as your body tolerates them. In week’s two to four you’ll start to include puréed food, followed by soft and mashed food. Finally by week six you’ll commence eating a healthy diet of solid foods that constitutes your long term eating plan.

The first few weeks after your Gastric Bypass

0-2 weeks post operation

Fluid regime

You’ll start taking sips of water the day of your operation and then clear fluids such as diluted fruit juices, clear broth, decaffeinated tea or coffee, low fat milk, Marmite and Bovril drinks, ice chips and sugar free popsicles. You’ll be offered a selection of these during your stay in hospital.

It’s common to experience nausea or vomiting at this stage as your body is recovering from the surgery.

Once you're handling clear liquids, you can progress to a full liquid diet with liquids that are smooth without lumps or seeds. Your diet will consist primarily of protein shakes, cream soups and clear liquids.

During this stage you may have small and frequent meals. Be sure to take little sips and stop when you feel full or any pressure.

The most important aspect of your diet immediately following gastric bypass surgery is to keep well hydrated. Make sure you keep sipping clear liquids between meals.

2-4 weeks post operation

Puréed regime

In week’s two to four, you can eat puréed food. All foods must be blended to a soft consistency like that of baby food.

Aim to eat small portions four to five times a day. A portion is half a cup to a cup, or five to six tablespoons of food. High protein-rich foods should be eaten first, followed by vegetables and lastly fruit.

Eat your meals slowly, taking small mouthfuls and chew your foods very well.

Your digestive system might be sensitive to spicy foods or dairy products. If you'd like to eat these foods during this phase try adding them into your diet slowly and in small amounts.

Continue to sip clear liquids throughout the day but do not drink with your meals. Wait 30 minutes before and after mealtimes before resuming fluids. If you drink whilst eating you will fill up too quickly, you may feel bloated or it may cause you to vomit and your nutrition will be compromised.

4-6 weeks post operation

Soft/mashed regime

In week’s four to six, you can start to eat soft and mashed food. Foods you can try include minced meat, fish, chicken, humous, scrambled eggs, cereals, cooked vegetables, canned fruits and rice pudding. Avoid foods high in sugar and fat.

You will reduce your meals to three to four times each day and eventually cut back to three meals a day and a couple of snacks.

Continue to introduce one new food at a time so that you can see how your body tolerates it.

Remember to always drink plenty of fluids throughout the day, every day, but not at meal times.

6 weeks onwards after having a Gastric Bypass

You’ll look forward to this stage as you may resume normal textured foods. You can gradually return to eating firmer foods but foods must still be chopped or diced initially. As you start eating solid foods again, you will initially feel full very quickly. Just a few bites of solid food will fill you up. This is because your new stomach pouch holds only a tablespoonful of food at first, about the size of a walnut.

Start slowly with regular foods so you can determine the foods you can tolerate. You may find that you still have difficulty eating spicier foods or foods with crunchy textures.

Even at this stage, there are foods you should avoid because they may cause gastrointestinal symptoms, such as nausea, pain or vomiting. Foods to avoid include nuts and seeds, popcorn, dried fruits, carbonated beverages, granola, stringy or fibrous vegetables, such as celery, broccoli, corn or cabbage, tough meats or meats with gristle, fried foods and breads. Over time, you may be able to try some of these foods again and see if your body will tolerate them, with the guidance of your bariatric team.

Make sure you’re getting enough protein, vitamins and minerals while you’re losing weight quickly. Eating mostly protein, fruits, vegetables and whole grains will help you achieve this.

Your pouch will get slightly larger over time but you don’t want to stretch it so don’t overeat. When your pouch is larger, it will still not hold more than about one cup of chewed food. A normal stomach can hold up to four cups of chewed food.

Difficulties and eating techniques

Proteins are important

After gastric bypass diet, eating is focused on providing the body with healthy proteins and nutrient rich foods. Your body needs protein to build muscles and other body tissues and to heal well after surgery. Protein is not stored in your body and so it must be eaten at every meal. It’s advised that you always eat your protein first to ensure you’re not too full to eat it.

Vitamin and mineral supplements

You’ll need to take daily vitamin and mineral supplements straight after your gastric bypass surgery and for the rest of your life. Your small intestine will no longer be able to digest all the vitamins and minerals your body needs from your diet. Most people are required to take:

  • A multivitamin supplement
  • A calcium supplement
  • An iron supplement

Watch your intake

You will be advised to consume 800 to 1000 kcal for the first one to two years during weight loss and then 1000 to 1200 kcal per day thereafter for weight maintenance.

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Spread the cost of your treatment

  • Fixed monthly payments over a term that enables you to budget
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