Nutritional Guidlines

It is very important that you follow a strict diet after your gastric sleeve

Following surgery, you will need to follow a specific nutritional plan for the first five weeks. This is very important. By following the nutritional guidelines set out below, you will reduce the chances of experiencing a sleeve complication and give yourself a good start to your weight loss journey.

There are three phases to your post-op diet.

These three phases are set out in more detail below for you.

Nutritional Advice

Phase 1: Liquid foods

You must follow a liquid diet for the first two weeks after your sleeve operation.

  • Liquids should be smooth and not contain any ‘bits’ as they may cause discomfort or pain or get stuck. Use a sieve if you are unsure
  • If a drink will go through a straw then it is the correct consistency for this stage. However, do not drink through a straw as you may take in a lot of air and this could cause discomfort
  • Sip slowly but frequently throughout the day at the start of the liquid stage, allowing a few minutes between sips. As the days go by, you can progress to cupfuls of drinks taken slowly over a 15 – 20 minute period. In the first two weeks after surgery, you can build up to taking around 200mls at any one time. If you experience pain, discomfort or regurgitate your drinks, take smaller sips and allow more time between sips. Some people find warm drinks go down more easily to start with; others find that sucking ice cubes can help if you are struggling to get fluids down
  • Avoid fizzy drinks in the early days after your operation as these may cause pain from trapped wind. Make sure that your drinks (especially nutritional drinks) are spread out over the day. If you go for long gaps without anything to drink you may start to feel light-headed and nauseous
  • Some people get a ‘furry mouth’ in the first month as when you have nothing to chew on, your mouth produces less saliva to protect your teeth. Using a mouthwash and brushing your teeth well will help. You could also try sugar free chewing gum, ice cubes and home made no added sugar squash ice lollies.

Dietary Instructions

Each day you may choose

  • Meal replacement shake (hot or cold)*
  • Bowl of soup
  • 400ml (2/3pt) semi-skimmed or skimmed milk
  • 400ml (2/3pt) soya milk with added calcium
  • 2 smooth diet yoghurts (125g each) to blend with milk or water to a ‘drinkable’ consistency
  • 3 heaped tablespoons skimmed milk powder
  • 15g protein powder e.g. soya or egg (obtainable from health food shops or a pharmacy); you may need to use these to obtain your protein if you do not like dairy products. They can be mixed into soups or fruit or vegetable juices

*Please note that when made strictly according to the box instructions, meal replacement shakes may be a little too thick at this stage. A thinner consistency can be achieved simply by adding more water and less (or no) ice. The resulting consistency should be similar to milk.

  • Oxo, Bovril, Marmite or stock cubes dissolved in hot water
  • Soups – tinned, dried, cuppa, homemade. You may need to dilute them with extra water or add an Oxo cube, Bovril or Marmite and sieve to remove all bits and lumps
  • 1 small glass (150ml) unsweetened fruit juice. If you have a juicing machine you can make your own tasty combinations e.g. beetroot and orange, carrot, celery and apple. Dilute with approximately 150ml water and sieve to remove all bits and lumps
  • 1 glass (200ml) vegetable juice e.g. carrot, tomato, mixed vegetable, V8
  • 1 x 100ml low-fat, low sugar Actimel or similar
  • 1 x 100 – 150ml Vie or other smoothie drinks
  • Low-calorie hot chocolate, Ovaltine or Horlicks
  • ½ banana or small portion of soft fruit to make into a ‘smoothie’ with milk; make sure this is a thin consistency and sieve to remove all bits and lumps
  • Water; plain or flavoured low-calorie variety (not carbonated)
  • Low-calorie, no added sugar or sugar-free squash
  • Tea, including herbal teas
  • Coffee, preferably decaffeinated

Sample Menu: Phase One

Below is an example of what you could be enjoying while during phase one post surgery.

8.00am – 150 – 200ml tea or coffee or water or unsweetened juice 

9.30am – half a meal replacement shake

11.00am – 200ml tea or coffee, squash, water

1.30pm – 150 – 200ml tea or coffee or water or unsweetened juice 

3.00pm – 200ml coffee

4.30pm – half a meal replacement shake

6.00pm – 150ml unsweetened orange juice 

7.30pm – half a bowl of soup

10.00pm – 200ml milk or yoghurt blended with milk/water

Phase 2: Puréed foods

Two weeks after your sleeve operation, the stomach tissues are still healing and it remains important not to stretch the small stomach with foods that are hard or indigestible. You should begin to make the transition from liquids to puréed foods. Do not eat larger quantities than recommended even if you feel that you could. Your newly created stomach could stretch and if you begin to eat larger quantities of food you may lose sensitivity to fullness.  

During this stage, you can continue to take drinks only if you prefer (as in the first two weeks) or start to have puréed food with a consistency like thick yogurt or a combination of both liquid and puréed foods. As an example of the progression in textures that you should aim for, start with your Weetabix as a sloppy mixture with plenty of low fat milk but progress towards your Weetabix being more solid with much less milk towards the end of this stage. You can begin to add fruit to the meal replacement shakes and use less water and more ice (as instructed on the box) to achieve a thicker consistency. 

It’s best to avoid more ‘difficult’ foods at this stage such as red meat, shellfish, bread (especially really fresh), fibrous fruit and vegetables including skins, dried fruit, nuts and rice. Fish and white meat are generally softer than red meat and can be mashed, although well cooked lean minced meat in sauce would be fine. If your food is ‘spoonable’ it is the correct consistency. 

  • Start by eating up to 5 small puréed ‘meals’ per day and then towards the end of this stage try to establish a 3 meal a day pattern of eating with soft foods
  • Your portion size should be about 3 – 6 tablespoons per meal. Never exceed 6 tablespoons for each meal even if you feel you could eat more. Serve your meals on a 7 inch side plate
  • Eat very slowly (take 15 – 20 minutes for each meal) to recognise the new feeling of filling up until you don’t want to eat more. Your stomach should now only hold about 2 tablespoons at the most, so when you have a meal that may be up to 6 tablespoons, some of the food will need time to pass through. Your timer can help you to slow down your eating
  • Stop eating when you no longer feel hungry. If food is left on your plate, throw it away
  • Your food may contain soft lumps but not any hard lumps, skins or pips etc as they may cause discomfort, pain or get stuck
  • Remember to drink calorie-free liquids, keep alcohol to a minimum and choose low-fat, low sugar foods to purée/mash

Dietary Instructions

Every day ensure that you choose foods from each of the following food groups:

  • Thick meal replacement shake (with or without fruit)
  • 1 soft/runny scrambled egg
  • 1 – 2 tbsp puréed chicken, Quorn, tofu, minced lamb or beef. Use sauce / gravy for smooth consistency
  • 1 – 2 tbsp of soft fish mashed into fine flakes
  • 1 small plain yoghurt (blended with fruit if desired)
  • 1 – 3 tbsp Ready Brek or porridge
  • 1 – 2 tbsp mashed potato
  • 1 – 2 tbsp soft mashed pasta
  • 1 – 2 tbsp puréed/ mashed veg (fresh, frozen, tinned)
  • 1 – 2 tbsp stewed/mashed fruit
  • Smoothie of 2 fruit portions with 150ml juice/milk
  • 1 x 250ml glass of fruit juice

Sample Menu: Phase Two

Below is an example of what you could be enjoying while during phase two post surgery.

Breakfast - select one from the list below

  • 1 small shake blended with fruit
  • 1 small portion of ready brek
  • 1 small portion of soft scrambled egg

Mid-morning snack - select one from the list below

  • 2 tbsp puréed fruit
  • 1 small smooth/plain low-fat yogurt

Lunch - select one from the list below

  • 1 Acti-Diet soup
  • 1 smooth low calorie soup

Lunch - select one from the list below

  • 1 Acti-Diet soup
  • 1 smooth low calorie soup

Mid-afternoon snack - select one from the list below

  • 1 Acti-Diet shake
  • 1 small smooth plain yogurt
  • 2 tbsp puréed fruit


  • 1-2 tbsp puréed chicken or fish in sauce and 1-2 tbsp puréed vegetables and 1-2 tbsp very soft mashed potato

IMPORTANT: Ensure you drink at least 2 litres of fluid per day 

Suitable drinks are tea, coffee, low-calorie diet drinks (avoid fizzy), water and herbal teas.

Phase 3: Normal foods

The gastric sleeve operation is designed to help you lose weight by restricting your food intake and increasing your sense of satiety (fullness) so that you feel satisfied from eating less. It also acts by reducing the absorption of food from the upper part of the small bowel. But if you are to be successful in the long term, you need to work with your sleeve with diet, portion control and physical activity. If you work hard, your sleeve will be a tremendously powerful aid to weight loss but if you expect the surgery to do all the work, you could be disappointed.

This stage is really the start of learning how to work with your gastric sleeve developing lifelong healthy eating habits to achieve your health and fitness goals. You must leave soft, sloppy food in the past and discover solid textured foods that remain longer in your stomach to stop you from feeling hungry.  

Recognising the full feeling

You must learn to recognise new feelings of hunger and fullness from your new smaller stomach . This is completely different from your previous ‘rumbly tummy’ hunger or ‘whole tummy; uncomfortably stuffed’ feeling of fullness. Your tummy below can still make rumbly, gurgly noises but actually you may not be hungry! Physical hunger is also completely different from eating out of boredom or comfort because when you do this, you will NEVER feel full because your body does not need food at this time. Most people acknowledge some sort of ‘emotional eating’ or ‘head hunger’. Your gastric sleeve cannot help you with this. You will need to identify times when this is likely to happen and develop behavioural strategies to tackle it before it sabotages your weight loss. 

There is considerable variation in how full people feel at any given time. Your stomach will feel smaller and more restricted on some days than others, so that whilst you may cope with a particular food on one day, you may not manage it quite so well on another.

Recognising the full feeling

For your sleeve to work effectively, food now needs to be of a ‘drier’ consistency, eaten and chewed slowly in small mouthfuls so that you learn to sense fullness and stop eating when you think you’ve had enough. From now, you can eat all foods but if you are introducing a food for the first time, we recommend you try it at home and chew it well so that you are confident you can eat it without discomfort or regurgitation. Be particularly careful with any of the ‘difficult’ foods that you may have avoided last month i.e. red meat, shellfish, bread (especially really fresh), fibrous fruit and vegetables including skins, dried fruit, nuts and rice. If you experience discomfort or food ‘sticking’ the first time you eat it, try again a week or two later perhaps chewed slightly longer and eaten even more slowly so that you know how much you can manage. 

  • Choose healthy, wholesome foods and no junk food. Your new eating plan has no room for wasted calories from sugary, fatty foods and your emerging new body needs good nutrients to keep you healthy and full of energy. Most fast foods and snacks are high in fat, salt or sugar. These are not good for your health or energy levels

  • Always choose foods low in fat and sugar. Yogurts and similar products like fromage frais should be ‘diet’ i.e. low in fat AND sugar. Meat and poultry should have fat and skin removed. Food should be baked, grilled, micro waved, steamed or stir fried, not deep fried. You then taste the food, not oil.

What shouldn't I eat?

Leave behind the milkshakes (protein shakes are okay), smoothies, gravy and sauces that you had in the last few months. Soft and liquid foods are not recommended because one tends to consume large volumes of them quickly, they pass through your system and you will soon be hungry again. If you frequently consume soft foods and drinks that are high in fat and sugar e.g. ice cream, cake, chocolate, milk shakes etc OR high calorie ‘crunchy’ foods such as crisps, biscuits etc you will not feel full and you will be tempted to consume larger quantities. This will prevent further weight loss and may lead to weight gain. 

How much should I eat?

An appropriate quantity of food should fit in the palm of your hand e.g. half an apple and this will keep you feeling full for longer. Use the timer provided to control the time you take between each mouthful.Your main meal should fit onto a 7 inch side plate or small bowl and be composed of foods in the following proportions:

  • One quarter protein (eg meat, poultry, fish, pulses)
  • One quarter starchy (eg potato, pasta, rice, bread, couscous)
  • One-half vegetables or salad (without butter, mayonnaise or rich dressings)

Start to ‘think thin’!

People who weigh less tend not to think about food too often, they eat slowly and consciously, don’t eat large portions, stop eating when they think they are full and often leave food on their plate. It is useful to develop these skills for permanent weight control. Get used to looking at your new portion size, eat without any distractions e.g. away from the television and concentrate on your food. Relax when eating, eat slowly and savour the tastes in each mouthful. It is a good exercise to try putting down your knife and fork between mouthfuls. Try it! Sit on your hands between mouthfuls if you are still trying to rush your food. You will soon start to eat in a more relaxed way and recognise when to stop eating so that you are comfortably full but not in discomfort. If food is left on your plate, throw it away; don’t keep it for later or act as the rubbish bin.

General advice for the solid food stage

  • Aim to eat 3 small meals per day and no snacks between. This will help you to establish new and appropriate hunger and fullness responses and keep your metabolism going. You will learn to eat when you are truly hungry and not for other reasons

  • Throw away the large plate and bowl and use a smaller diameter plate/bowl as research shows that when people eat from large plates and bowls, they tend to eat more. You might also want to try using a cake fork – very small bites indeed!

  • Take small mouthfuls. Large mouthfuls will fill your stomach too quickly and you may suffer regurgitation. Also large mouthfuls are more likely to trap air in your stomach, causing discomfort

  • Eat and drink SLOWLY. Each time you swallow it takes 10-20 seconds for food to pass from your mouth into your stomach and then 20 minutes for nerve and chemical signals to reach your brain from your stomach to register a ‘feeling of fullness’. If you eat too quickly, you pass the point of fullness before you stop eating and will suffer pain, choking or regurgitation. Chew slowly, put your knife and fork down between mouthfuls. Use the timer provided to control the time you take between each mouthful

  • Allow at least 20 minutes for each meal. You may need to plan extra time for meals so that you are able to eat slowly, not gulp large mouthfuls and recognise fullness. A rushed meal may be uncomfortable

  • Stop when you’re no longer hungry – NOT when you are full. You will need to learn the point at which you feel physically full but not in pain or discomfort. If you experience pain rather than ‘fullness’ you have had too much to eat or drink.

  • If you choose to eat ‘soft’ foods, you MUST restrict your portion size to 1-2 tablespoons then fill the rest of your side plate with vegetables or salad. 

  • Drink low or zero calorie drinks water eg Bovril, low calorie squash, herbal teas, tea or coffee (restrict to 4 cups per day with a little low fat milk and no sugar to avoid excess caffeine)

  • Keep alcohol to a minimum. Alcohol is full of calories that will stop you losing weight so it is best avoided. It may also make you forget your good eating plans!

  • Drink frequently. Sometimes you may actually be thirsty rather than hungry.  Always try a drink before reaching for something to eat. Have 1.5 litres of fluid every day, this will help to avoid constipation, headaches and dehydration

  • Don’t drink with your meals. You will need to drink up to 15 minutes before your meal then leave 2 hours after your meal before drinking again; this will help you to feel full for longer by not washing your food out of your stomach.

The main food groups

Below are the main food groups you should have a balanced diet of:

Also includes rice, noodles, oats, breakfast cereals, pasta, sweet potatoes, beans, lentils and dishes made from maize, millet and cornmeal. These foods should make up about one third of your diet. Have one or two portions at each meal time (3 – 4 portions/day). Choose wholegrain, wholemeal or high fibre varieties to help your digestive system. 

People often think that starchy foods are particularly fattening. This isn’t true, but starchy foods become fattening if they’re served or cooked with fat. For example, it is the butter we spread on bread, the cream or cheese sauce we add to pasta or the oil we use for frying that makes them fattening. So cut down on these added fats rather than the starchy foods themselves.

Portion sizes (2 – 3 servings daily)
  • 1 slice bread or toast

  • 1 crumpet

  • 2 crisp breads / 3 small crackers

  • 2 small oat cakes

  • ½ pitta or 1 small pitta

  • 1 small chapatti

  • 3 tablespoons dry porridge oats

Try to include at least 3 vegetable/salad portions daily. Make sure that for your main meals at least half of your plate (side plate size) is full of a variety of vegetables/salad. You can use tinned, frozen or fresh vegetables. 

Portion sizes (3 – 5 servings daily) 

  • 3 heaped tbsp cooked vegetables

  • 1 side salad (half a side plate size)

  • 1 medium/ 7 cherry tomatoes, glass vegetable juice

  • Use a wide selection of raw, cooked and salad vegetables e.g. aubergine, beetroot, broccoli, cabbage, celery, courgette, cucumber, gherkins, leeks, lettuce, mushrooms, okra, peppers, radish, spring onions, swede, tomatoes, turnip, watercress

Aim for 2 – 3 portions per day. It is vital to include at least two portions daily from this group, because on your new eating plan it may be difficult to obtain enough protein in the small portions that you will be eating. Trim visible fat from meat, choose lean cuts wherever possible and remove skin from chicken before cooking. Meat such as bacon and salami and products such as sausages, beefburgers and pâté are all relatively high fat choices, so try to keep these to a minimum. Beans, such as canned baked beans and pulses, are a good low-fat source of protein. Aim to eat at least two portions of fish a week. These can be fresh, frozen or tinned.

Portion sizes (2 – 3 servings daily)  

  • 100g (3½oz) very lean cooked beef, pork, lamb, chicken, turkey, liver, kidney, pilchards, salmon

  • 150g (5oz) cooked white fish or tinned tuna (in brine or spring water), tofu or Quorn

  • 2 eggs (limit to 6 per week)

  • 4 tbsp cooked peas, lentils, beans (including baked beans), kidney beans etc

This group is important for calcium to keep your bones and teeth strong and includes milk, cheese, yoghurt and fromage frais. For a healthy diet eat moderate amounts of these foods (2 – 3 portions per day). Choose semi-skimmed or skimmed milk, low-fat yoghurt (0.1% fat or less), virtually fat free fromage frais and reduced fat cheeses. (Note: when buying yoghurt or fromage frais, make sure that they are low in fat AND low in sugar).

Portion sizes (2 – 3 servings daily)   

  • 200ml semi-skimmed milk

  • 1 small pot of diet yoghurt or fromage frais

  • 100g (4oz) cottage cheese

  • 60g (2oz) low-fat soft cheese

  • 25g (1oz) hard cheese e.g. cheddar, stilton

Fruit can be used as a snack if necessary, chopped on cereal or as a dessert after a meal. Fruit should only be consumed if you are truly physically hungry.

Portion sizes (2 servings maximum daily)   

  • 1 medium piece fresh fruit – apple, orange, ½ banana

  • 2 – 3 small fruits e.g. plums, apricots

  • 150g (5oz) strawberries, raspberries, blackberries

  • 3 tbsp stewed or tinned fruit (no added sugar)

  • 1x100ml glass fruit juice (one per day)

  • 1 heaped tablespoon dried fruit

  • 1 handful of grapes

Sample Menu: Phase Three

Below is an example of what you could be enjoying during phase three post surgery. 

Breakfast - select one from the list below

  • 1 Shredded Wheat with skimmed or semi-skimmed milk

  • ½ slice toast with scraping of low-fat margarine AND 1 boiled egg AND 2 tablespoons boiled mushrooms OR 1 piece of very lean bacon grilled with 1 fresh tomato

  • 3 tablespoons All Bran with a little skimmed / semi-skimmed milk, no added sugar AND 1 tablespoon raisins OR ½ banana / 8 – 10 nuts eg hazelnuts, brazil nuts, almonds / 1 flat tablespoon seeds e.g. pumpkin
  • 3 tablespoons Fruit and Fibre / Special K / no added sugar muesli with a little skimmed / semi-skimmed milk and no added sugar.

Lunch - select one from the list below

  • ½ tin tuna in brine or spring water and 1 – 2 crisp breads or crackers
  • ½ slice toast and mixed salad with lemon and herbs and ½ apple or 1 satsuma

Evening Meal

  • 2 fish fingers and 2 small new potatoes in skins and crisply cooked vegetables or a mixed salad and 1 diet yoghurt or diet fromage frais and ½ banana or handful of strawberries, raspberries etc.

IMPORTANT: Ensure you drink at least 2 litres of fluid per day 

Suitable drinks are tea, coffee, low-calorie diet drinks, water and herbal teas.

Additional Suggestions


  • 3 tbsp Fruit and Fibre, Special K, no added sugar muesli with a little skimmed or semi-skimmed milk and no added sugar

  • 3 tbsp All Bran with a little skimmed or semi-skimmed milk, no added sugar AND 1 tbsp raisins OR ½ banana OR 8 – 10 nuts e.g. hazelnuts, brazil nuts or almonds OR 1 flat tbsp seeds e.g. pumpkin

  • ½ slice toast AND 1 boiled egg AND 2 tbsp boiled mushrooms OR 1 piece of very lean bacon grilled with 1 fresh tomato


The portion sizes are approximate and may be too much. You will need to use your new eating skills to determine when you are full, i.e. eating slowly, small mouthfuls, concentrating on your food, enjoying each mouthful, putting your knife and fork down between mouthfuls. Stop eating when you sense that you do not want to eat any more.

Remember: if you choose to eat ‘soft’ foods, you MUST restrict your portion size to 1 – 2 tablespoons then fill the rest of your side plate with vegetables or salad. You may finish a ‘soft’ meal with ½ apple or other crunchy fruit.

  • ½ tin tuna in brine or spring water and 1 – 2 crisp breads or crackers

  • ½ slice toast and mixed salad with lemon and herbs and ½ apple or 1 satsuma

Some suggested meals:

  • ½ piece baked fish in breadcrumbs with 2 small new potatoes and 2 portions of lightly cooked vegetables

  • ½ tandoori chicken breast with 1 tbsp basmati rice and mixed salad

  • Small piece fresh tuna, baked or grilled (about ‘pack of cards size’) with 1 tbsp pasta + 1 tsp pesto to flavour and salad

  • 2 slices roast meat with 2 small ‘dry roast’ potatoes and 2 portions of lightly cooked vegetables and 1 tsp sauce or gravy

  • ¼ large pizza with mixed salad

  • Stir fry with chicken, beef, tofu or pork pieces, sugar snap peas, mini sweetcorn, carrot, onion etc, and a little soy sauce. Serve around 3 tbsp

  • 1 tbsp pasta, cooked ‘al dente’ mixed with 1 tsp pesto, 1 fresh chopped tomato and ½ boiled chicken breast. Serve with salad

  • 1 small baked potato with tuna in brine or spring water mixed with 2 tsp low-fat mayonnaise and lemon juice or vinegar and mixed salad

  • 2 pieces of liver*, lightly brushed with oil, baked or grilled with 2 small new potatoes and 2 portions of lightly cooked vegetables

  • 2 small slices of bread (wholegrain or granary) with 2 slices of lean meat or chicken and salad

NB. * Do not eat liver if you are pregnant

Snacks (if required)

If you have eaten your 3 small, solid/dry textures meals and are still physically hungry, occasionally as a snack you could have:

  • Small handful of nuts / 1 small piece of fruit / 1-2 cream crackers with light spread / handful of popcorn
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