Bariatric dietitian handbook

Liver-reducing diet

What is the purpose of a liver-reducing diet?

The liver-reducing diet (LRD) is a diet that is low in energy (calories), particularly carbohydrate and fat.

By following a liver-reducing diet that is low in calories, your body will use the carbohydrate (glycogen) stored in the liver. The glycogen, and some of the water stored with it, will leave the liver. The liver will shrink and become softer, more flexible and easier to move during surgery.

During laparoscopic (keyhole) surgery, the liver has to be lifted out of the way to access the stomach beneath it. Some people having bariatric surgery have a large, fatty liver, which can make keyhole surgery more difficult.

A large, fatty liver makes it harder for the surgeon to see and gain access to the stomach underneath. This can increase the duration of your surgery and therefore the time spent under general anaesthetic.

It can also increase the risk of your liver bleeding during surgery and injury to other organs. If this happens, the surgeon may have to change to open surgery instead of keyhole surgery.

If you do not follow the liver-reducing diet and your liver has not shrunk, surgery may be deemed unsafe and the surgeon may cancel the surgery on the day.

Important: Are you taking weight loss injections?

This includes drugs such as Ozempic, Mounjaro, Wegovy and Saxenda. If you are, you must follow the SlimFast plan (Option 1).

This is important as these drugs slow the rate at which food moves through your digestive system. You must have an empty stomach for your bariatric surgery. Liquid nutrition moves much more quickly than solid food, which is why SlimFast is the only suitable option.

How long will I have to follow the liver-reducing diet?

The duration of the diet is based on the following criteria:

• If your BMI is lower than 50kg/m²: 2 weeks
• If your BMI is greater than 50kg/m² and/or you have additional comorbidities, such as type 2 diabetes, sleep apnoea or non-alcoholic fatty liver disease: 4 weeks

BMI means body mass index, measured in kg/m².

Your bariatric team will advise you how long you need to follow the diet.

What are the liver-reducing diet options?

• Option 1: SlimFast meal replacement diet
• Option 2: Milk and yoghurt diet
• Option 3: Food-based diet

All of these diets are designed to provide:

• around 800–1,000 kcal
• less than 100g of carbohydrate
• low fat
• high protein

You are required to pick one of the options and follow it as instructed.

Please do not mix different diet options as this may not produce effective results.

Option 1: SlimFast meal replacement diet

SlimFast is a nutritionally complete, low-calorie diet meal replacement product.

With this diet you are required to have:

• 4 x 325ml pre-made SlimFast bottles per day
• 2 cereal bowls of salad or vegetables from the list below

These can be blended into soup, boiled, steamed, roasted or eaten raw.

Suitable vegetables

• artichoke
• asparagus
• aubergine
• broccoli
• Brussels sprouts
• butternut squash
• cabbage
• carrot
• cauliflower
• celery
• courgette
• cucumber
• edamame beans
• green beans
• runner beans
• leek
• lettuce and other leafy greens
• mangetout
• marrow
• mushroom
• onion
• peppers
• pumpkin
• shallots
• spinach
• spring onion
• sugar snap peas
• swede
• tomato
• turnip

How can you make your salad and vegetables interesting?

Season your food with herbs, chilli, spices, garlic and pepper.

Use lemon juice and vinegar, including balsamic vinegar, to flavour salads and vegetables. Avoid adding oil or ready-made dressings.

A note on hydration

Aim to have at least 2 litres of fluids per day, including:

• water
• sugar-free squash
• herbal tea
• black tea
• black coffee without sugar

You are allowed to have 1 salty drink a day to help maintain electrolyte levels. For example, dissolve 2 teaspoons of stock, Marmite®, Bovril® or consommé in a large glass of warm water.

Please note that you are not allowed to have powdered SlimFast as it is too high in calories and carbohydrate.

Four SlimFast shakes per day will provide:

• 816 kcal
• 60g protein
• 88g carbohydrate
• 20g fibre
• 21g fat

Option 2: Milk and yoghurt diet

This diet is based only on milk, yoghurt and additional fluids.

Alcohol and all other food sources should be avoided for the duration of this diet.

Daily intake

• 3 pints of skimmed, semi-skimmed, lactose-free or soya milk per day. The milk can be hot or cold and flavoured with vanilla essence or sugar-free syrups, such as Crusha or Monin
• 2 x 125g low-fat plain or natural yoghurt, or 0% fat yoghurt, per day. Aim to avoid fruit yoghurts as they can be high in sugar and fat. You can add sugar-free syrups or flavourings to plain or natural yoghurt if needed
• an additional minimum of 2 litres of fluid per day, such as water, calorie-free or low-calorie squash or flavoured water, tea, coffee and fruit or herbal teas

Avoid adding sugar to tea or coffee. You can use sweeteners instead. You can use milk from your daily allowance in tea or coffee.

You will need to start taking a multivitamin and mineral supplement once a day as this diet is not nutritionally complete.

Examples include Sanatogen A–Z, Tesco’s A–Z, Centrum Advance or Performance and Holland & Barrett.

You are allowed to have 1 or 2 salty drinks a day to help maintain electrolyte levels. For example, dissolve 2 teaspoons of stock, Marmite® or Bovril® in a large glass of warm water.

Example milk and yoghurt diet

Breakfast:

• 400ml milky coffee
• 125g low-fat plain or 0% fat yoghurt

Snack 1:

• 300ml glass of milk

Lunch:

• Oxo or Bovril drink
• 300ml glass of milk

Snack 2:

• cup of tea with 100ml of milk
• 300ml glass of milk

Dinner:

• Oxo or Bovril drink
• 125g low-fat plain or 0% fat yoghurt

Snack 3:

• 300ml glass of milk

Option 3: Food-based diet

This diet is based on low-carbohydrate, low-energy, low-fat and moderate-protein meals with additional fluids throughout the day.

Your meals should follow the format below:

Breakfast

• 1 carbohydrate portion
• 1 dairy portion

Lunch

• 1 carbohydrate portion
• 2 protein portions
• 2 vegetable portions
• 1 fat portion

Evening meal

• 1 carbohydrate portion
• 1 protein portion
• 1 vegetable portion
• 1 dairy portion
• 1 fat portion

Snacks

2 pieces of fruit per day, which can be eaten at any time.

What is a portion?

Protein

• Raw lean meat, such as beef, pork, lamb or chicken: 100g, approximately the size of a pack of playing cards
• Ham, chicken or turkey: 4 thick or 8 thin packet slices, approximately 100g
• Fish, such as salmon, trout, cod, haddock or mackerel: 1 fillet, approximately 125–150g
• Canned tuna in brine or spring water: 1 can, approximately 160g
• Eggs: 2, not fried
• Baked beans: 4 tablespoons
• Lentils, kidney beans, chickpeas, butter beans, tofu or Quorn: 4 tablespoons
• Nuts: 2 tablespoons

Vegetables

• Cooked vegetables, such as carrot, broccoli or cauliflower: 3 tablespoons
• Side salad: the size of a cereal bowl
• Tomatoes: 1 tomato or 6–8 cherry tomatoes

Fruit

• Apple, pear, banana, orange or peach: 1 piece
• Melon: 1 slice
• Grapes: 12
• Strawberries: 7
• Plums, apricots, satsumas or kiwi: 2
• Tinned fruit, such as peaches or pears: 3 tablespoons
• Stewed fruit, such as apples or rhubarb: 4 tablespoons
• Raisins or sultanas: 1 tablespoon
• Goji berries: 1 tablespoon
• Dried apricots: 3

Dairy

• Skimmed, semi-skimmed, soya or lactose-free milk: 1 medium glass (200ml) or one-third of a pint
• Low-fat or soya yoghurt: 1 small pot (150g)
• Light fromage frais: 1 small pot (150g)
• Low-fat cheese, such as feta, quark, reduced-fat cheddar or reduced-fat mozzarella: 1 matchbox-sized piece (30g)
• Light cream cheese: 30g
• Cottage cheese: half a large pot (100g)

Carbohydrates

• Breakfast cereals, such as Bran Flakes, Rice Krispies or Special K: 3 tablespoons
• Muesli or porridge: 2 tablespoons
• Shredded Wheat or Weetabix: 1
• Bread or toast: 1 medium slice
• Pitta bread: half a pitta or 1 mini pitta
• Wholemeal bread roll: half a roll
• Crackers: 3
• Crispbreads: 4
• Chapatti: 1 small
• Cooked rice: 2 tablespoons
• Cooked couscous: 2 tablespoons
• Cooked pearl barley: 2 tablespoons
• Cooked quinoa: 4 tablespoons
• Cooked pasta: 3 tablespoons
• Cooked noodles: 100g
• Potatoes or sweet potato: 2 small egg-sized portions
• Plantain: half, approximately 100g
• Yam: 70g
• Cooked cassava: 50g
• Muesli bar: 1

Fats

• Butter or margarine: 1 teaspoon
• Reduced-fat or low-fat spread: 2 teaspoons
• Low-fat or light salad dressing: 2 teaspoons
• Oil: 1 teaspoon

Example meal plan

Breakfast: 1 carbohydrate portion and 1 dairy portion

• 3 tablespoons of cereal with 200ml semi-skimmed milk, or
• 1 Weetabix with 200ml semi-skimmed milk, or
• 1 slice of toast with 30g low-fat cheese

Snack: 1 fruit portion

• 1 banana

Lunch: no carbohydrate portion, 2 protein portions and 2 vegetable portions

• 200g grilled chicken with 6 tablespoons of vegetables or salad, or
• 1 can of tuna in spring water with 6 tablespoons of vegetables or salad, or
• 8 tablespoons of Quorn or tofu with 6 tablespoons of vegetables or salad

Dinner: 1 fruit portion

• 12 grapes

Snack: 2 carbohydrate portions, 1 protein portion, 1 vegetable portion and 1 dairy portion

• 6 tablespoons of pasta with minced beef in 4 tablespoons of homemade bolognese sauce and 30g low-fat grated cheese with a small side salad, or
• 4 tablespoons of bean or chickpea stew with 4 tablespoons of cooked rice, 3 tablespoons of low-fat yoghurt and a small mixed-leaf salad

Foods to avoid

It is important to avoid foods high in sugar and fat, including:

• sweets
• chocolate
• cakes and biscuits
• jelly
• ice cream
• sugary drinks, including juices and fizzy drinks
• alcohol
• sugar added to hot drinks or food. Sweeteners can be used instead
• crisps
• fried foods and takeaways
• creamy or ready-made pasta or meal sauces. Choose tinned tomatoes for cooking instead, for example in bolognese sauces, stews or casseroles
• meat or fish products with breadcrumbs. Choose fresh, lean alternatives

Fluids

Aim for a minimum of 2 litres of fluid per day, including:

• water
• tea or coffee. You can add milk from your daily dairy allowance
• sugar-free squash or sugar-free flavoured water that is not fizzy

You will need to start taking a multivitamin and mineral supplement once a day as this diet is not nutritionally complete. Examples include Sanatogen A–Z, Tesco’s A–Z, Centrum Advance or Performance and Holland & Barrett.

Additional information

You may experience headaches or feel light-headed after starting the liver-reducing diet. This is quite usual and usually passes after the first few days.

Constipation can become a problem when following this diet because it contains very little fibre. If you need help with constipation, speak to your GP or pharmacist.

If you have diabetes and take medication, including tablets or insulin, contact the person who normally helps you manage your diabetes. You may need to reduce your insulin or tablets as all of the liver-reducing diets are low in carbohydrate, containing less than 100g, and can result in your blood glucose falling lower than normal.

Check your blood glucose levels 4 times a day. If you do not have a blood glucose meter, you can ask to have your blood glucose checked at your local pharmacy. Please contact your dietitian if you experience regular hypos, or low blood glucose levels.

It is expected that you will experience some weight loss during the liver-reducing diet. You may therefore experience a change in your menstrual cycle during this period. Women with polycystic ovary syndrome (PCOS) may ovulate and become fertile while following the liver-reducing diet, so it is important to use contraception.

You need to stop eating 6 hours before your surgery. You are only allowed to have water up to 2 hours before your surgery.

Protein after bariatric surgery

This information is designed to help you understand the importance of protein-rich foods in your diet after bariatric surgery.

Why is protein important to have in my diet?

Protein is important because it:

• is an essential building block for the body and helps preserve muscle mass as you lose weight
• is necessary for growth and repair, including recovery after surgery
• helps you feel fuller for longer and supports achieving a healthy weight
• helps your body fight infections

After bariatric surgery, it is important to have a protein-rich food at each meal.

Ideally, you should aim to have 70–100g of protein a day.

Examples of protein-rich foods

• Eggs: 2 large eggs provide approximately 13g of protein
• Skinless chicken: 1 chicken breast (200g raw or 160g cooked) provides approximately 31g of protein
• Fish, such as salmon: 1 salmon fillet (150g raw or 120g cooked) provides approximately 22g of protein
• Lean red meat, such as beef: 1 steak (200g raw or 160g cooked) provides approximately 26g of protein
• Beans, such as kidney beans: half a tin (200g drained) provides approximately 9g of protein
• Pulses, such as lentils: half a tin (200g drained) provides approximately 9g of protein
• Greek yoghurt: 100g provides approximately 10g of protein
• Soya milk: 200ml provides approximately 3.3g of protein
• Tofu: 150g provides approximately 8g of protein
• Quorn: 100g provides approximately 13g of protein

These foods are also good sources of some essential vitamins and minerals, including:

• vitamins A, B and D
• iron and zinc

Top tips

1. Plan your menu in advance and base your meals and snacks around foods that are high in protein.
2. Choose low-fat varieties of lean meat and remove any visible fat. Avoid adding fat when cooking these foods.
3. Chew meat, chicken and fish well before swallowing to avoid it getting stuck.
4. Eat slowly.
5. You may find roasted meats more difficult to tolerate. If this is the case, try alternative ways of cooking meat, such as stewing, casseroling, slow cooking or mincing, or choose wafer-thin meats.

Eat the protein-rich foods in your meal first.

Protein supplementation after bariatric surgery

After bariatric surgery, it can be difficult to meet your protein requirements because your food intake is very small. You need adequate protein as your ability to absorb protein is not as efficient as it was before surgery.

• Protein is essential for your body to heal and maintain muscle mass while you are losing weight.
• Ideally, aim to include at least 70g of protein in your diet each day.

Using a protein supplement can be a useful way to achieve this, particularly in the first 6 months following your operation.

The ideal protein supplements are made from dairy protein, such as whey or casein protein, egg white protein or soya protein. These are the most readily absorbed by your body and contain complete protein.

A complete protein, or whole protein, contains all 9 essential amino acids necessary to meet your dietary needs in the correct proportions.

Choose protein supplements that are low in calories, carbohydrate and fat but high in protein. Look for one that contains the least amount of calories for the most protein.

Whey protein powder is the most readily available protein supplement and can be found in many supermarkets and health food stores. Ideally, it should be made with skimmed milk as this will further increase the protein content for the same volume of fluid.

Dairy-free alternatives

If you require lactose-free or dairy-free options, you can choose plant-based alternatives such as:

• soya protein
• pea-based protein
• hemp protein

Protein products should not be used as an alternative to whole-food sources of protein. These products should be used to complement a healthy, balanced diet.

Protein-rich snacks

• 10 almonds: provides approximately 4g protein
• apple with 1 tablespoon of peanut butter: provides approximately 4g protein
• 1 boiled egg: provides approximately 6g protein
• carrot with 75g light cottage cheese: provides approximately 6g protein
• 85g roasted chickpeas: provides approximately 5g protein
• 50g low-fat Greek yoghurt with berries: provides approximately 6g protein

Golden Rules

Also known as the 20/20/20 rule.

Eat slowly

Allow 20 minutes to eat a meal. Aim to eat every 2–3 hours.

Chew and chew

Chew your food well and count to 20.

Avoid eating and drinking together

Allow at least 20 minutes before eating and after eating before having a drink.

Portion control

Use a smaller plate or cutlery.

Avoid

Avoid foods high in fat and sugar, fizzy drinks, fruit juices and alcohol to reduce the risk of dumping syndrome.

Remember protein first.

Texture progression diet after surgery

This information will guide you through the post-operative stages step by step after gastric bypass or sleeve gastrectomy surgery.

The texture progression phases from fluids to solids are important to reduce the risk of unpleasant side effects such as nausea, vomiting, pain and discomfort. The gradual texture progression also helps to avoid damage to your new stomach, allows your wounds to heal after surgery and allows food to pass easily from the stomach to your small intestine.

It is important not to skip any of the stages.

You will need to follow a modified texture diet for 6 weeks before returning to a regular-texture diet. The diet is separated into 4 stages:

• Smooth iquids
• Purée
• Soft and moist (fork-mashed)
• Regular (normal)

The day after your surgery, your surgical team will tell you when it is safe for you to begin to sip fluids.

Stage 0: While remaining as an inpatient (1–2 days)

What can I have?

• water
• ice chips
• clear consommé on the ward
• sugar-free jelly
• no-added-sugar or sugar-free squash
• tea, coffee, milk and protein-based drinks

Key points

• take small sips at a time
• avoid gulping large quantities
• aim to drink 5–6 cups per day, approximately at least 1.5 litres

When the surgical team are happy with your progress, you can move to Stage 1.

Stage 1: Only smooth liquids for 2 weeks (days 0–14)

All liquids should be completely smooth with no bits or lumps. Start with sips, little and often, and if you feel comfortable then gradually increase the amount. Avoid big gulps as this may cause discomfort, nausea, sickness and regurgitation.

Choose liquids that are high in protein to help meet your protein requirements. The average recommendation is 70–100g each day. Aim to have 1.5–2 litres of fluids each day to stay hydrated.

Always prioritise protein-rich fluids over others, such as tea and coffee. Begin by sipping your drinks little and often and gradually increase the quantity until you begin to feel full.

It is important to stop as soon as you feel full. If you drink too much, your stomach may overfill and cause pain, nausea and vomiting.

Which liquids are suitable?

Choose at least 1 litre (2 pints) of protein-rich liquids each day to help your body recover, such as:

• skimmed or semi-skimmed milk, with dried skimmed milk powder or protein powder if required
• high-protein shakes, either powdered or ready-made
• high-protein soups, such as Optifast, Meritene, Build-up, Complan or Fast 800 soup
• low-fat natural or plain yoghurt drinks
• kefir or ayran drinks
• protein water and clear whey
• liquidised and sieved smooth high-protein homemade soups with a milk-like consistency, such as lentil, chicken or chickpea soup. You can add skimmed milk powder or flavourless protein powder

Other fluids you can have:

• still water
• Marmite® or Bovril®
• clear soups
• herbal or fruit teas
• tea and coffee, using sweeteners rather than sugar
• no-added-sugar or sugar-free squash
• sugar-free jelly
• diluted vegetable juice with no bits

Fluids to avoid:

• fruit juices, malt drinks and fruit smoothies
• fizzy drinks, including fizzy water, as the gases may cause bloating, pain and can increase your stomach size
• all alcohol

Sample meal plan

• Breakfast: high-protein shake
• Snack: 200ml glass of skimmed milk with 1–2 teaspoons of skimmed milk powder
• Lunch: high-protein soup
• Snack: yoghurt drink
• Evening meal: high-protein shake
• Snack: 200ml glass of skimmed milk with 1–2 teaspoons of skimmed milk powder

How much and when?

Try to have 1.5–2 litres of fluids each day. Aim for at least 1 litre (2 pints) of milk-based fluids and always prioritise protein-rich fluids over others, such as tea and coffee.

Begin by sipping your drinks little and often and gradually increase the quantity until you begin to feel full.

It is important to stop as soon as you feel full. If you drink too much, your stomach may overfill and cause pain, nausea and vomiting.

Stage 2: Purée for 2 weeks

All food during this stage should be puréed and completely smooth with no bits or lumps.

It is important to complete this stage as your stomach pouch will be very small and tight at first. Puréed foods are smooth and can pass through your stomach easily. You will need to use a blender, liquidiser or food processor to purée your food to the correct consistency.

Aim for a smooth consistency like yoghurt.

Choose foods that are high in protein to help meet your protein requirements of at least 70g each day. Aiming for at least 500ml (1 pint) of protein-rich fluids daily will help you achieve this.

How much and when?

Eat 3 meals and 3 snacks each day. Start with 1–2 tablespoons at your meals and snacks and, if you feel comfortable, gradually increase the amount.

As you progress through the purée stage, you may find that your portions gradually increase. However, remember to stop eating at the first signs of fullness or if you feel uncomfortable.

If you eat too much, you may experience pain, nausea and vomiting.

Which foods are suitable?

The main focus for your meals and snacks is protein, so always eat this first. All of the foods below will need to be puréed.

Foods from other food groups, such as carbohydrates, fruit and vegetables, are also suitable but are not a rich source of protein. If you choose to eat these, add some extra protein such as protein or skimmed milk powder, high-protein yoghurt, skimmed milk or low-fat cheese to fortify them.

Protein

• chicken, lamb, beef and turkey
• fresh or tinned fish
• Quorn or soya mince
• beans and pulses, such as lentils, chickpeas, kidney beans and baked beans
• light cream cheese or low-fat cottage cheese
• smooth low-fat high-protein or natural yoghurt, or fromage frais
• low-fat smooth hummus
• soup containing a protein-rich food

Carbohydrates

• white potato and sweet potato
• yam, cassava and plantain
• Weetabix or Ready Brek with plenty of milk
• pasta or rice
• porridge

Fruit and vegetables

• fresh, frozen or tinned vegetables without skins or seeds, cooked and puréed, such as carrots, courgettes, parsnips and broccoli
• fresh, frozen or tinned fruit, peeled, cooked and puréed, such as apple, pear and blueberries

Foods to avoid

Avoid any food that has not been puréed with a blender, liquidiser or food processor.

Suitable fluids

Try to choose protein-rich liquids between your meals:

• skimmed or semi-skimmed milk, with dried skimmed milk powder or protein powder if required
• high-protein shakes and protein water
• high-protein soups
• yoghurt drinks, kefir and ayran

Other fluids you can have:

• still water
• Marmite®, Bovril®, consommé or bouillon
• clear soups
• herbal or fruit teas
• tea and coffee, using sweeteners rather than sugar
• no-added-sugar or sugar-free squash
• sugar-free jelly
• diluted vegetable juice with no bits

Fluids to avoid:

• fruit juices, malt drinks and fruit smoothies
• fizzy drinks, including fizzy water, as the gases may cause bloating, pain and can increase your stomach size
• all alcohol

Aim to drink 1.5–2 litres of fluids each day.

Sample meal plan

Breakfast: Weetabix, Oatibix or Ready Brek with plenty of skimmed milk, or a high-protein yoghurt pot or pouch.

Lunch and dinner ideas:

• puréed chicken with potato and vegetables
• puréed minced meat in bolognese sauce with puréed vegetables
• puréed lentil and vegetable soup
• puréed chicken and vegetable soup
• puréed tinned fish, such as tuna, sardines or mackerel, with potato and vegetables
• puréed potato with grated cheese or cream cheese

Half your meal portion should be from a protein-rich food. Try adding 2 teaspoons of protein or skimmed milk powder to your puréed foods.

Aim for 2–3 snacks across the day: a 200ml glass of skimmed milk with 1–2 teaspoons of skimmed milk powder, a protein shake or high-protein yoghurt.

Stage 3: Soft and moist foods for 2 weeks

Once you have completed the purée stage, you can move onto soft foods. It is important to follow this stage as your stomach is still healing and recovering from surgery.

What is soft food?

Soft foods have a soft consistency, are well cooked and can be easily mashed with a fork. You do not need to use a blender during the soft stage.

Foods to avoid

Avoid foods that are hard or contain skins, seeds and pips as these will be difficult to mash into a soft consistency.

• sweetcorn, peas, celery, fresh tomato, potato skin, nuts, seeds and hard cheese
• dry, crumbly foods such as biscuits and crackers
• foods with a mixed consistency, such as minestrone soup or cereal flakes with milk

How much and when?

Eat 3 meals each day and, if you feel hungry between meals, have a snack. Use a side plate for your main meals and fill half of your plate with protein-rich foods.

Start with 3–4 tablespoons at meal times and stop eating at the first signs of fullness or if you feel uncomfortable. If you eat too much, you may experience pain, nausea and vomiting.

Sample meal plan

Breakfast ideas:

• porridge, Oatibix or Weetabix with skimmed milk
• mashed baked beans
• soft cooked eggs, such as scrambled eggs, poached eggs or an omelette

Lunch and dinner ideas:

• tinned or soft flaky fish with mashed potato and vegetables
• shepherd’s pie or cottage pie with mashed vegetables
• minced chicken, beef, lamb or turkey with couscous, mashed potato and vegetables
• minced Quorn or soya mince with pasta and vegetables
• omelette with low-fat grated cheese and mashed, peeled, seedless tomato
• cauliflower cheese
• braised chicken or meat casserole
• chicken, fish or lentil curry or stew with vegetables and mashed potato or couscous
• thick soups such as lentil, chicken, ham or pea

Snack ideas:

• 200ml glass of skimmed milk with 1–2 teaspoons of skimmed milk powder
• high-protein shake
• high-protein yoghurt
• low-fat custard
• low-fat yoghurt

Suitable fluids

Try to choose protein-rich liquids between your meals:

• skimmed or semi-skimmed milk, with dried skimmed milk powder or protein powder if required
• high-protein shakes
• protein water
• high-protein soups

Other fluids you can have:

• still water
• Marmite®, Bovril®, consommé or bouillon
• herbal or fruit teas
• tea and coffee, using sweeteners rather than sugar
• no-added-sugar or sugar-free squash
• sugar-free jelly
• diluted vegetable juice with no bits

Fluids to avoid:

• fruit juices, malt drinks and fruit smoothies
• fizzy drinks, including fizzy water, as the gases may cause bloating, pain and can increase your stomach size
• all alcohol

Aim to drink 1.5–2 litres of fluids each day.

Stage 4: Regular foods from 6 weeks onwards

You will now have completed 6 weeks of texture progression and your stomach should have healed enough for you to gradually introduce regular-texture foods and increase the variety of foods in your diet.

Continue to eat 3 regular meals each day and try not to leave more than 4–5 hours between meals. You should not graze, which means eating small amounts of food constantly throughout the day, or go for a long period without eating.

Use a side plate to help guide your portions and follow the bariatric plate model below so that you are always prioritising protein first.

If you are hungry between meals, choose a nutritious snack such as a piece of fruit, high-protein yoghurt or a glass of skimmed milk.

Bariatric plate model

Aim for your plate to consist of:

• Half protein: choose lean protein foods first, such as chicken, fish, eggs, beans or pulses
• One quarter vegetables: choose non-starchy vegetables
• One quarter carbohydrates: choose high-fibre carbohydrates in small portions

Possible problem foods

There may be foods after a gastric bypass or sleeve gastrectomy that some people find difficult to tolerate and feel like they get stuck or may make you sick.

These include chewy or dry red and white meat, bread, fibrous fruit and vegetables, rice, pasta, nuts and seeds.

Avoid these at the beginning of the regular stage and then reintroduce them gradually once a regular diet has been established.

What should I do if food gets stuck?

This may happen because:

• you have eaten food that was too solid
• you have eaten too quickly or too much
• you have eaten certain problem foods

This will feel uncomfortable and you may retch or vomit. Often it will resolve itself. However, you could try drinking a small amount of cold sparkling water, as the fizz may help to dislodge the food that is stuck.

Side effects

Vomiting

After surgery, vomiting can occur. It is often the result of:

• eating too much
• eating too quickly
• not chewing your food well enough
• eating and drinking together or too closely together
• eating foods that are not the correct consistency for the stage you are in

If you continue to vomit after checking the above and you are still within the first 2 months after surgery, you could try returning to the purée or liquid phase for a short period to see if your symptoms improve.

If you continue to vomit and the cause cannot be explained, contact your surgeon or GP. Very occasionally, there may be a narrowing where the new joins in your intestine have been created. This may require a procedure to stretch the area so food can move through.

Dumping syndrome

After surgery, avoid foods and drinks high in sugar and fat. If these are consumed, even in small amounts, they can cause dumping syndrome.

Symptoms can include:

• nausea
• sweating
• abdominal cramps
• palpitations, or a rapid heart rate
• diarrhoea
• dizziness
• feeling faint

Dumping syndrome occurs when fatty or sugary foods are emptied, or ‘dumped’, from the stomach into the small intestine too rapidly.

It is usually easy to identify dumping syndrome and the food or drink that has triggered it, as symptoms usually occur within 30–60 minutes after consumption.

If you experience dumping syndrome, try to sit or lie down until your symptoms improve.

In the longer term, avoiding fatty and sugary foods will help you manage dumping syndrome and help you achieve your weight-loss goal.

Reactive hypoglycaemia

Reactive hypoglycaemia, or low blood glucose, is a recognised complication after surgery and is the result of changes to your intestine, hormonal changes and the way you digest carbohydrates.

Symptoms can include:

• sweating
• palpitations, or a rapid heart rate
• feeling shaky
• dizziness
• feeling faint
• confusion
• weakness

Symptoms of reactive hypoglycaemia usually occur within 1–4 hours after a meal.

If you think you are experiencing reactive hypoglycaemia, contact one of the bariatric dietitians for advice. Reactive hypoglycaemia can often be managed with dietary changes.

Keeping a food and symptom diary is essential to identify foods that trigger symptoms.

If dietary changes do not help you manage reactive hypoglycaemia, the dietitian will refer you to endocrinology for further investigations and advice.

Hair loss

During the first 6–9 months after surgery, you may experience rapid hair loss due to rapid weight loss.

Following a healthy, balanced diet with enough protein and taking your vitamin and mineral supplements should help your hair return to normal.

Do not take combined hair, skin and nail supplements such as Perfectil.

Constipation

If you experience constipation, make sure you are drinking enough fluids. You should aim for 1.5–2 litres of fluids each day.

During the early post-operative stages it can be difficult to get enough fibre as your focus is on protein. When you are in the purée stage, include some puréed cereals, fruit and vegetables in your diet to help your bowels work more efficiently.

If constipation persists, speak to your GP about a suitable laxative.

Hunger and appetite

In the early post-operative period, you may not feel hungry because of your smaller stomach and changes in gut hormones that affect your appetite.

It is still important to eat 3 regular meals and snacks if needed, with the main focus on your protein intake.

A regular meal pattern with your smaller stomach can be a challenge and, with reduced feelings of hunger, you may be tempted to skip meals thinking that this may speed up your weight loss.

However, this can result in you becoming malnourished and deficient in protein, vitamins and minerals.

Skipping meals may also encourage unhelpful eating behaviours such as snacking or grazing that, in the longer term, may result in weight regain.

Lactose intolerance

Some patients experience lactose intolerance after bariatric surgery.

Lactose is a type of sugar found in dairy products such as cheese, milk and yoghurt. Normally, an enzyme called lactase is produced in the small intestine, which helps break down and digest lactose.

Lactose intolerance is estimated to affect 30% of patients after surgery.

Why can this happen after bariatric surgery?

• Foods and liquids move more quickly from the stomach into the small intestine, which can overwhelm the available lactase enzyme and leave some lactose undigested.
• Lactase secretion from the small intestine may be reduced following bypass surgery.

Symptoms of lactose intolerance

• diarrhoea
• abdominal pain
• bloating
• excess gas
• nausea after consuming dairy products

Treatment

To manage lactose intolerance, follow a lactose-free diet and monitor whether your symptoms improve.

Some people can eventually tolerate small amounts of lactose without symptoms.

Some people use lactase tablets or drops before eating lactose-containing foods. These supplements break down lactose to help reduce symptoms.

Typical doses are 3,000–9,000 FCC units, with higher amounts needed for foods such as milk or ice cream. Tolerance varies, so results differ. Always follow the product instructions and consult a healthcare professional if you are unsure.

Tip: Soya milk has the highest protein content after cow’s milk, with almond milk containing the least. Vegan protein shakes are also good lactose-free alternatives.

If symptoms persist or worsen after eliminating lactose from your diet, please contact us.

Pancreatic exocrine insufficiency (PEI)

Pancreatic exocrine insufficiency occurs when the pancreas does not produce enough enzymes to properly break down food.

This can lead to poor digestion and reduced absorption of nutrients, especially proteins, fats and carbohydrates.

Some research suggests it may affect around 9% of people, but more studies are needed to confirm this for OAGB patients.

Why can this happen after bariatric surgery?

• A large part of the small intestine is bypassed, meaning the pancreas receives less stimulation and may produce fewer enzymes.
• The enzymes mix with food later in the digestive tract, reducing the time available for proper digestion, particularly of fats.

Common symptoms

• diarrhoea
• steatorrhoea, which is diarrhoea containing excess fat and can cause greasy, yellow, foul-smelling stools that are difficult to flush
• wind
• bloating
• cramps

Diagnosis

The bariatric team or your GP will ask you to provide a stool sample and test your faecal elastase, which is a marker of pancreatic function.

Treatment

Treatment involves replacing the enzymes that your pancreas cannot produce. These are called pancreatin and are available under brand names such as Creon and Pancrex.

Taking these supplements with food containing fat will help your body absorb nutrients normally again and resolve your symptoms.

You will start on an initial dose and work with a dietitian for ongoing dose support.

Dietary management

• eat smaller, more frequent meals to aid digestion and reduce bloating
• stay hydrated to replace fluids lost through diarrhoea
• follow a balanced diet to help prevent nutritional deficiencies

Bile acid malabsorption (BAM)

Bile acids help the body digest fats and are normally reabsorbed in the small intestine. Bile acid malabsorption occurs when these acids are not fully absorbed, leading to irritation in the colon and chronic diarrhoea. This can develop after bariatric surgery.

Why can this happen after OAGB?

• A section of the small intestine is bypassed, reducing bile reabsorption.
• Bile flows directly into the intestines in larger amounts.

Common symptoms

• frequent watery diarrhoea
• urgency
• bloating
• excess gas
• fatigue

Diagnosis

A SeHCAT scan will be performed to test how well your intestines absorb bile acids. This involves swallowing a small capsule containing a mild radioactive tracer and, after 1 week, completing a scan to assess how much bile acid remains in the body.

Treatment

Medicines called bile acid binders are often prescribed. These help trap excess bile acids and reduce diarrhoea.

Dietary management

• reduce the amount of fat in your diet to help reduce bile acid production
• eat smaller, more frequent meals to prevent large bile releases
• stay hydrated to replace fluids lost through diarrhoea

Small intestinal bacterial overgrowth (SIBO)

This occurs when too many bacteria grow in the small intestine, leading to digestive symptoms.

Normally, the small intestine has fewer bacteria than the colon. When bacteria multiply in the wrong place, they can ferment undigested food.

This is seen in 30–77% of patients after bariatric surgery. It is more common with mini gastric bypass.

Why can this happen after OAGB?

• bypassing part of the small intestine changes the balance of bacteria
• bile reflux alters the gut environment
• reduced stomach acid can support bacterial growth
• slower movement of food through the intestines allows bacteria to grow

Common symptoms

• bloating
• excess gas
• diarrhoea
• unintentional weight loss
• fatigue
• fatty or greasy stools
• nutrient deficiencies

Diagnosis

A hydrogen or methane breath test will be performed. This involves drinking a sugar solution and measuring the hydrogen or methane in your breath.

As bacteria produce gases, a rise in gas levels may suggest bacterial overgrowth.

Treatment

A short course of antibiotics can resolve SIBO in most cases.

Dietary management that may help prevent recurrence

• reduce certain carbohydrates that feed bacteria, such as dairy products containing lactose, sugary foods and artificial sweeteners
• eat small meals frequently to help food move through the intestines
• stay hydrated to support good gut movement
• follow a high-protein diet and choose foods such as lean meat, fish, tofu and eggs
• introduce gut-friendly foods such as yoghurt, kefir and miso gradually

Vitamins and minerals

After surgery, reduced food intake and malabsorption increase your risk of vitamin and mineral deficiencies.

Daily, lifelong vitamin and mineral supplementation is essential.

As soon as you are able to start having puréed food, you can begin taking your multivitamins and minerals.

Remember to space your vitamins and minerals across the day, as taking them all together will affect how well you absorb them.

You will need to take your iron supplement separately from your multivitamin and mineral supplement and calcium.

Forceval

Multivitamin and mineral supplement.

Dose: 1 tablet each day
Duration: Lifelong

Adcal D3 chewable

Calcium supplement.

Dose: 2 tablets a day
Duration: Lifelong

Ferrous fumarate

Iron supplement.

Dose: 210mg tablet each day
Duration: For women while menstruating

Colecalciferol

Vitamin D supplement.

Dose: 20,000 units once each week or 3,000 units each day
Duration: Lifelong

Vitamin B12

Dose: 1mg intramuscular injection every 3 months
Duration: Lifelong, prescribed by your GP

NSAIDs

What are NSAIDs?

Non-steroidal anti-inflammatory drugs (NSAIDs) are medicines used to treat a range of conditions, including pain, inflammation and fever.

They are commonly used in the short term to treat conditions such as:

• headaches
• soft tissue injuries such as sprains and strains
• painful periods
• fever associated with colds and flu
• toothache

They are also often used to treat long-term conditions such as arthritis, including rheumatoid arthritis and osteoarthritis, and chronic neck or back pain.

Why can’t I take NSAIDs after bariatric surgery?

NSAID use increases the risk of developing a marginal ulcer.

This is a stomach ulcer occurring at the staple lines in the pouch or at the connection between the intestines in gastric bypass surgery. These can happen at any time after surgery.

Marginal ulcers

Marginal ulcers can cause:

• upper abdominal, or epigastric, pain
• nausea
• vomiting
• food intolerance
• excessive weight loss
• gastrointestinal bleeding
• iron deficiency

In some cases, they can cause gastrointestinal perforation, where a hole develops in the wall of the stomach or intestine. This is a serious and life-threatening condition.

Common NSAIDs

• aspirin in doses greater than 600mg
• ibuprofen
• celecoxib
• indometacin
• diclofenac
• mefenamic acid
• etoricoxib
• naproxen

Other NSAIDs include aceclofenac, acemetacin, dexibuprofen, dexketoprofen, etodolac, fenoprofen, flurbiprofen, ketoprofen, meloxicam, nabumetone, piroxicam, sulindac, tenoxicam and tiaprofenic acid.

Smoking

Smoking cigarettes at any point within the 12 months before surgery increases the risk of short-term surgical complications in bariatric patients.

It is recommended that you avoid all nicotine-containing products before and after surgery.

Risks of smoking before surgery

• associated with abnormal heart rhythm during anaesthetic
• increases the risk of lung complications and respiratory failure, which may require respiratory support in intensive care
• nicotine increases the thickness of the blood, increasing the risk of blood clots and heart attack

Risks of smoking after surgery

• smoking reduces the amount of oxygen reaching your skin, slowing wound healing
• increases the risk of wound-related complications, including wound breakdown and infection
• increases the risk of stomach ulceration, which can cause vomiting, pain, internal leakage and perforation

Ways to quit

Many people try to quit smoking using willpower alone, but it is much easier to stop smoking with the right help.

There are lots of support options available to help you on your quitting journey. You may want to consider the cost of different aids and their side effects.

If you have tried to quit before, think about what methods worked for you and what you might want to do differently.

The key is not to give up. Try different combinations until you find the one that works for you.

You can ask a doctor or pharmacist for advice about what is right for you or get free expert support from a stop smoking service.

Pregnancy after bariatric surgery

Bariatric surgery is an effective treatment option to reduce the risks of weight-related comorbidities and provide additional benefits in terms of fertility and pregnancy outcomes in women of childbearing age.

However, it is recommended that you avoid pregnancy for at least 18 months after bariatric surgery as you will be experiencing rapid weight loss during this period.

You are therefore at greater risk of nutritional deficiencies, which may cause both maternal and foetal complications during pregnancy.

You are recommended to use contraception during the first 18 months after surgery.

Oral contraception may not provide sufficient protection after bariatric surgery, particularly following malabsorptive procedures such as gastric bypass, as lower absorption rates are suspected.

It is therefore recommended that you use an alternative method of contraception.

Please refer to our contraception handbook for more information.

You can have your contraception organised through Chelsea and Westminster Hospital. The team can discuss your options and prescribe your chosen method.

You can also discuss contraception with your GP or gynaecologist before having bariatric surgery.

What happens when I find out I am pregnant after my surgery?

• Speak to your GP about referral to an obstetrician at your local hospital. Your GP will need to inform the obstetrician of the importance of serial ultrasound examinations every 4–6 weeks to evaluate foetal growth from the 24th week of gestation, especially in women with poor weight gain, as there is a possible increased risk of intrauterine growth restriction and small for gestational age in pregnancies following bariatric surgery.
• Contact the Bariatric Service immediately and tell them about your pregnancy so follow-up appointments can be arranged with the bariatric dietitians.
• You will be invited to attend regular follow-up appointments with the bariatric dietitians at least every trimester. It is important to ensure you are eating the correct balance of nutrients and identify any nutritional deficiencies at an early stage so these can be managed or treated.
• You will need regular nutritional blood tests at least every trimester, either at the hospital or through your GP practice.

Useful links for pregnancy

• Foods to avoid in pregnancy
• Breastfeeding and diet

After your bariatric surgery

Surgical wound closure

• Depending on your surgeon, your wounds may be closed in a number of ways.
• If you have surgical staples or non-absorbable sutures, these will need to be removed at your GP practice 10 days after surgery.
• If you have absorbable sutures, you may remove your dressing after 5–7 days and the sutures will dissolve by themselves.
• Please check with the ward nurse which type of wound closure you have before discharge.

Bathing

• Getting your wound wet is not recommended during the first week as this may cause infection.
• The dressing can be changed 5 days after discharge.
• If there is any oozing, redness or swelling, please see your practice nurse.
• Once the wounds are healed, you can shower, but we do not recommend having a bath for 14 days after surgery.

Pain

• We advise that you take the painkillers you have been given. If they are not helping with the pain, please contact your GP or the Clinical Nurse Specialist.

Physical activity and lifting

• Strenuous activity or heavy lifting should be avoided for around 6 weeks.
• Lifting will put pressure on your wound, which needs time to heal.
• We recommend gentle walking every day to assist with weight loss.

Sexual activity

• You may resume your normal sexual activity as soon as it feels comfortable for you.

Eating and drinking

• You have been given post-surgery dietary information. You are advised to follow it strictly.

Time off work

• We recommend taking 2 weeks off work after surgery.
• If you have a manual job, this may need to be increased or you may need to negotiate restricted duties.
• Please ask ward staff to arrange your fit note before you are discharged.

Driving

• Driving should not be attempted for 2 weeks or until you feel confident that you are able to perform an emergency stop.
• Please check with your insurance provider regarding its policy on abdominal surgery.

Contact the Bariatric Dietitians

If you have any questions, please contact the Bariatric Dietitians.

Telephone: 020 3315 8161
Email: chelwest.bariatric.dietitians@nhs.net

Bariatric checklist

Please bring your checklist to all your appointments and group sessions.

• Golden Rules – date of knowledge check: __________
• Importance of protein – date of knowledge check: __________
• Protein challenge – date of knowledge check: __________
• Liver-reducing diet (LRD) – date of knowledge check: __________
• Post-operative texture progression diet – date of knowledge check: __________
• Caution and problem foods – date of knowledge check: __________
• Side effects after surgery – date of knowledge check: __________
• Post-operative vitamins and minerals – date of knowledge check: __________
• Alcohol policy – date of knowledge check: __________
• Smoking policy – date of knowledge check: __________
• Pregnancy policy – date of knowledge check: __________