Post-Surgery Diet Advice

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Immediately after your bariatric surgery (bypass, sleeve or band), 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 drinks and food as time goes on. Recovery will vary from patient to patient but it can take three to six months for your body to settle.

Initially post-surgery your diet will be limited to liquids for the first 3 to 4 weeks, starting with water for the first few hours and moving on to full (non sugary/fizzy) liquids, such as milk, as your body tolerates them. In week 4 you’ll start to include puréed food, followed by soft and mashed food, and then crispy textures. Finally by week ten you’ll commence eating a healthy diet of solid foods that constitutes your long term eating plan.

You will be advised to avoid certain foods for the first few weeks and may or may not be able to manage some foods such as chewy meats or doughy bread on a more longer term basis.

Common foods to be cautious of for the first few months:

  • Bread - especially doughy bread
  • Overcooked rice or pasta
  • Chapattis
  • Lettuce
  • Pips, seeds, skins, pith (peel first initially)
  • Dried fruit
  • Sweetcorn
  • Nuts
  • Stringy vegetables e.g. green beans, celery
  • Grilled, roast or fried meat and chicken (stick to minced/wafer thin)

Avoid all fizzy and sugary drinks long-term.

The first few weeks/months after your Bariatric Surgery

Stage 1: Fluids only - follow this stage for 3-4 weeks

You’ll start taking sips of water the day of your operation (after approval from your surgeon), and then move on to other clear fluids such as diluted fruit juices, tea or coffee, low fat milk or Marmite and Bovril drinks. It’s common to experience nausea or vomiting at this stage as your body is recovering from the surgery. You will be offered anti sickness medication in hospital and given some to take home as well.

If you can handle clear liquids, you can progress to a full liquid diet with liquids that are smooth without lumps or seeds i.e thin enough to go up a straw. Your diet will consist primarily of protein shakes/water, milk, soups and clear liquids. You must avoid all fizzy and sugary drinks.

The most important aspect of your diet immediately following bariatric surgery is to keep well hydrated. Make sure you keep sipping clear liquids between ‘meals’ (more calorific/high protein drinks). Take little sips and stop when you feel full or any pressure. Dietitians usually suggest starting with 200ml/hour and building this up as tolerated. Aim for 1.5 to 2 litres of fluid a day (all drinks count towards this amount).

You should aim to consume at least 60g of protein a day within a week after your surgery i.e. 3 pints of nutritious drinks such as milk or meal replacement drinks (or protein shakes) and an additional 1 pint of clear fluid such as water or squash. Consuming enough protein a day not only helps your body to recover from surgery but helps to minimise muscle loss whilst you are losing weight. Take a complete chewable A-Z multivitamin during this time, as well as your antacid prescribed e.g. lansoprazole.

Stage 2: Introducing Purees only - follow this stage for 3 weeks

In this stage, all foods must be blended or mashed to a soft consistency like that of baby food. Aim to eat small portions 5 to 6 times a day i.e. 3 meals and 2-3 snacks 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 or carbohydrates. You may still need 1 to 2 pints of nutritious fluid (e.g. milk) during this stage to help meet your protein needs of 60g/day.

Eat your meals slowly, taking small mouthfuls (no bigger than a 20p piece) and chew your foods very well (20 times before swallowing). Your digestive system might be sensitive to spicy foods so 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 taking a drink. 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.

Your dietitian will provide you with an example meal plan.

Stage 3: Introducing soft & crispy foods - follow this stage for 2-3 weeks

Around 6-7 weeks after your bariatric surgery, you can start to eat soft and mashed food. Aim for the texture of shepherd’s pie or dhal. Foods you can try include minced meat, fish, chicken, hummus, scrambled eggs, cereals, cooked vegetables, canned fruits (in juice not syrup) and rice pudding (no added sugar). Avoid foods high in sugar and fat.

Aim for three meals a day and a couple of healthy 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. You may still need 1 pint of nutritious fluid (e.g. milk) during this stage to help meet your protein needs of 60g/day.

Once you can comfortably manage soft foods, try adding crispy things such as crispbreads, crackers, bread sticks, very crispy toast. Avoid anything doughy such as bread or chapattis as these are still likely to cause you a problem. You can gradually start to include the ‘caution foods’ mentioned earlier at this stage too.

Your dietitian will provide you with an example meal plan.

Stage 4: Introducing ‘Normal Texture’ Foods & Beyond

Three to six months after bariatric surgery, most people find that they can manage ‘normal texture’ foods, but this will vary from person to person. Don’t worry if you are not quite there yet.


  • Continue to eat soft foods as before and gradually introduce small amounts of normal texture foods as well.
  • Chew food very well and take your time.
  • Continue to leave at least 30 minutes between eating and drinking.
  • Remember to stop eating before you feel full to avoid discomfort/vomiting.
  • Sit at the table to eat. Do not eat whilst doing other things such as watching TV or reading. You will be much more aware of how much you are eating if you are not distracted.
  • Eat regularly - skipping meals is an easy way to gain weight as your hunger levels may be increased later in the day.
  • Aim to eat 3 meals a day and work towards a maximum of a small dinner plate per meal. Once you are able to manage this amount you should no longer need snacks. If you are still hungry add more protein, vegetables or salad to meals and have fruit or yoghurt as a healthy snack.
  • If you are eating well and managing plenty of high protein foods at each meal then it will no longer be necessary to include extra milky drinks.
  • Practice good, permanent eating habits – just because you can get away with eating something now and still lose weight does not mean you will be able to forever

Important Notes

Vitamin and Mineral Supplements - You’ll need to take daily vitamin and mineral supplements straight after your bariatric surgery and for the rest of your life. Most people are required to take:

  • A multivitamin supplement
  • A calcium and vitamin D supplement
  • An iron supplement
  • A vitamin B12 injection every 3 months (prescribed by your GP)

Calorie Intake

You will be advised to consume around 600 to 800 kcal for the first few months and then 1000 to 1500 kcal per day thereafter for weight loss and then weight maintenance.

Portion Control

At meals fill 1⁄2 a small plate with lean protein (such as meat, fish, poultry, eggs, low-fat cheese, pulses and lentils), 1⁄4 with vegetables or salad, and 1⁄4 with starchy carbohydrates (such as basmati rice, pasta, baby new potatoes or couscous). Ideally choose whole wheat varieties as they have more fibre.

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