Liver shrinkage diet for Bariatric Surgery


What is the purpose of a liver shrinkage diet?

Liver shrinkage diet (LRD) is a diet based on low energy (calories), in particular low in carbohydrate and fat.

By following a liver shrinkage diet, your body will be forced to use up the stored carbohydrate (glycogen) from the liver. The glycogen and a quantity of water will leave the liver, and therefore 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 lying beneath it. Most people needing bariatric surgery have a large, fatty liver which can cause difficulty for keyhole surgery.

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 your time under general anaesthetic.

It can also be dangerous as your liver could bleed heavily during surgery or there could be injury to other organs. If this happens the surgeon may have to do open surgery instead of keyhole surgery.

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

How long will I have to follow the liver shrinkage diet?

Duration of the diet is based on below criteria: 

What are the liver shrinkage diet options?

OPTION 1 - SlimFast Meal Replacement Diet

OPTION 2 - Milk and Yogurt Diet

OPTION 3 - Food based Diet

All of the above diets are designed to provide:

  • Around 800-1000kcal
  • Less than 100g of carbohydrate
  • Low fat
  • High protein 

You are required to pick one of the options and follow it as per instructions. Please do not mix different diet options as it will not show effective results.


SLIMFAST® is a nutritionally complete, low calorie diet (LCD) meal replacement product. With this diet you are required to have:

  • 4x 325ml (pre-made) SLIMFAST® bottles per day.
  • 2 x cereal bowls of salad/vegetables from the list provided below: (cooking method: blended into soup/boiled/steamed/roasted/raw)

How can you make your meal interesting?

  • Season your food: Add herbs, chilli, spices, garlic, salt and pepper freely
  • Skip the ready-made dressings: Avoid adding any oil or salad dressings.

Lemon juice and vinegar (including balsamic vinegar) is allowed.

  • Keep hydrated: Aim to have at least 2 litres of fluids per day including: water, sugar free squash, herbal tea, black tea, black coffee (no sugar).
  • You are allowed to have 1 salty drink a day to help maintaining electrolyte levels.For example: 2 teaspoons of Stock or Marmite or Bovril or Consommé dissolved in a large glass of warm water.

Please note you are NOT ALLOWED to have the powdered version of SlimFast as it is high in calories and carbohydrate.


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

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

Daily intake:

  • 3 pints of skimmed OR semi skimmed milk OR lacto-free OR soya milk per day. The milk can be hot/cold and flavoured with vanilla essence, SUGAR FREE syrups (e.g. Crusha, Monin).
  • 2 x 125g low-fat plain or natural yogurt or 0% fat yogurt per day. Aim to avoid fruit yogurts as they can be high in sugar and fat. You can add sugar free syrups or flavourings into the plain/natural yogurt to adjust the taste if needed.
  • An additional minimum of 2litres of fluid per day (i.e. water, calorie free or low calorie squash/flavoured water, tea/coffee, fruit/herbal teas)
  • Avoid adding any sugar into your tea/coffee. Sweeteners are allowed to be used as an alternative. You can use milk from your daily allowance to add into your tea or coffee.
  • You will need to aily as this diet is not nutritionally complete. For example: Sanatogen A-Z, Tesco’s A-Z, Centrum Advance/Performance, Holland and Barrett.
  • You are allowed to have 1 or 2 salty drink a day to help maintaining electrolyte levels. For example: 2 teaspoons of Stock or Marmite or Bovril or Consommé dissolved in a large glass of warm water. 



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

Your meals should follow the below format:


  • 1 carbohydrate portion
  • 1 dairy portion


  • NO carbohydrate
  • 2 protein portions
  • 2 vegetable portions


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


  • 2x pieces of fruit per day - can be taken anytime

What is a portion?

Example of a meal plan:

Foods to avoid:

It is important you avoid any foods high in sugar and fat, this includes:

  • Sweets
  • Chocolate/cakes
  • Jelly
  • Ice cream
  • Sugary drinks including juices/fizzy drinks
  • Alcohol
  • Sugar added to hot drinks/ food (sweeteners are allowed to be used as alternative).
  • Crisps
  • Fried foods/ takeaways
  • Creamy or ready-made pasta or meal sauces (choose tinned tomatoes to use in cooking i.e. in bolognaise sauces/stews/casseroles).
  • Meat/fish products that have breadcrumbs (choose the fresh / lean options)


Minimum of 2L of fluids including:

  • Water
  • Tea/Coffee (you can add milk from your daily dairy allowance – see above)
  • Sugar free squash/ sugar free flavoured water

You will need to start taking a multivitamin and mineral supplementation once daily as this diet is not nutritionally complete. For example: Sanatogen A-Z, Tesco’s A-Z, Centrum Advance/Performance, Holland and Barrett.

Additional Information

  • You may experience headaches or feel “light-headed” after starting the liver shrinkage diet; this is quite usual and will pass in the first few days.
  • Constipation can become a problem when following this diet because it contains very little fibre. You may need to take 1-2 sachets of Fybogel each day or any other laxatives in the tablet or powder form in order to prevent this. We do not recommend taking Lactulose during pre-op liver shrinkage diet.
  • Patients on insulin or gliclazide (tablets): If you have diabetes and take insulin injections or gliclazide (tablets) please contact the person who normally helps you control your diabetes. It is likely you will need to reduce your insulin or gliclazide because the diets are all low in carbohydrate (less than 100g) and will make your blood sugars go lower than normal. Check your blood glucose levels 4 times a day. If you do not have a blood meter, you can ask to have your blood sugar checked at your local pharmacy. Please contact to your dietitian if you experience regular hypo’s (low blood sugar levels).
  • It is expected that you experience some weight loss during liver shrinkage diet. Therefore; female patients need to be aware that you may experience a change in your menstrual cycle during this period. Additionally, women with PCOS (polycystic ovary syndrome) may ovulate and become fertile while on liver shrinkage diet, therefore it is important to use contraception.
  • Please note you need to stop any food consumption 6 hours prior to your surgery and you are only allowed to have water up to 2 hours prior to your surgery. 


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