Section 4a: Before surgery – liver shrinkage and the preoperative diet

Section 4a: Before surgery – liver shrinkage and the preoperative diet  

Why do I need to follow a pre-op diet? 

The pre-op diet is required in order to shrink your liver, which allows your surgeon to operate more easily and safely. The diet achieves this by containing a maximum of 100g of carbohydrate and 1000kcal (calories) per day, which forces the stores of glycogen (carbohydrate) in your liver to reduce. 

You may also need to lose a certain amount of weight before surgery, either by the request of your surgeon/consulting practitioner or to qualify for admission to a certain hospital. The diet will also assist with achieving this. 

If you fail to follow this diet, you run the risk of having your procedure cancelled or abandoned, and the cost of procedure cannot be refunded. Do not be tempted to have a special meal or larger meal before surgery, as this will reverse the liver-reducing effects of the diet. 

Do I need to speak to a dietitian before the surgery? 

Yes. Your Surgeon Assistant will arrange a preoperative consultation (face-to-face or telephone) with the dietitian to discuss the pre-operative diet and the short- and long-term post-operative dietary guidelines which are crucial for success. You will receive an email confirming the date and time. It is imperative that you keep this appointment; if you are unsure of when your appointment is, please contact your Surgeon Assistant. 

How long do I need to follow a pre- operative diet for? 

This depends on your BMI: 

 Please note this is just a guide and your surgeon or consulting practitioner may advise differently. You should always follow their advice.  

What if I have diabetes? 

If you have diabetes and are treated with insulin, liraglutide (Victoza), exenatide or a sulphonylurea tablet (glicazide, glibenclamide, tolbutamide, glimepiride, glipizide), you may need to adjust the dose of your insulin or medication. Please contact your Diabetes Specialist Nurse / Practice Nurse / GP before starting the pre-operative diet. 

Do I need to take any supplements during the pre-operative diet? 

It is recommended you take a multivitamin and mineral supplement for the duration of the pre-operative diet, as it will vastly reduce your intake. Any brand is suitable providing it is complete – it must contain vitamins and minerals. Good quality off-the-shelf varieties include: 

• SanatogenComplete A-Z 
• Tesco A-Z Multivitamins and Minerals
• Lloyd’s Pharmacy A-Z Multivitamins and Minerals
• Superdrug A-Z Multivitamins and Minerals

A variety called Forceval is also available on prescription or over-the-counter. It is also available in a soluble form, so can be used in the initial period after surgery when solid tablets are not to be taken. 

Does the pre-operative diet have any side-effects? 

You may become dehydrated and constipated as a result of the reduced carbohydrate in the pre-op diet, and so you will need to drink at least 2 litres of additional fluid per day. 

 Suitable fluids include water, ‘no added sugar’, ‘sugar free’ or ‘diet’ flavoured water/squash/cordial/fizzy drinks, tea (including fruit/herbal varieties) and coffee. Any milk should be taken from the allowance given in the plan you choose. No sugar is allowed, but you can use any type of artificial sweetener. Caffeinated drinks can also be included. If you wish to have a savoury drink, you may have an Oxo or Bovril. 

This dramatic change in dietary habits can also cause other unpleasant side-effects including lower energy levels, headaches, mental dullness, temporary dizziness, nausea, diarrhoea, sluggish mobility and bad breath (you can have sugar-free chewing gum to help with this). 

What are the options for the pre-operative diet? 

There are 3 options: 

1. Option 1 is based on liquids (milk or meal replacement drinks) and yogurts
2. Option 2 is based on solid food, with a vegetarian option available
3. Option 3 is a mixture of the two above 

Option 1:  Liquids (milk or meal replacement drinks) and yogurts 

STEP ONE

• Choose your milk or meal replacement from the first column of table 1

STEP TWO

• The second column of table 1 tells you how much milk or how many meal replacements you can have per day

STEP THREE

• Choose 1 yogurt or 1 portion of milk to have in addition per day from table 2 

Table 1 

Please make up the meal replacements as instructed by the manufacturer.  

Table 2 

If you find a yogurt that is not listed, it must provide a minimum of 5g protein and no more than 110kcal and 10g carbohydrate per portion. 

Please note regarding meal replacement products: If you want to use a meal replacement product that is not listed, please speak with your dietitian before doing so, as many are not suitable for the pre-operative diet.  

Option 2: Solid food 

This plan consists of food which you can incorporate into your day as you wish. If you do not eat meat or fish, there is a vegetarian option available – please ask your dietitian in your preoperative appointment for a copy of this.  

 All food must be weighed using digital kitchen scales. IMPORTANT: The weighing of food is crucial to ensure accuracy. Do not estimate anything. If you feel you will not be able to do this, we would strongly recommend that you follow Option 1 or 3 instead as they require less weighing and measuring. Please note that the weights given are the maximum allowed, but you do not have to have the full amount. 

Number of Portions Allowed 

The table below shows how many portions of each food group you are allowed per day. 

If there are any foods not listed that you would like to include, please mention this to the dietitian. If nutritional information for the food/product is available, they can work out the portion size in grammes. 

Carbohydrate – 3 per day

 NOTE: 1 carbohydrate portion equates to 2 vegetable/salad/beans/pulses portions, if you wish to swap to these instead. If you are choosing gluten free alternatives, the portion size is the same as the gluten-containing food listed above. Weights of wholemeal/brown options are the same.  

Protein – 2 per day 

Vegetables/salad/beans/pulses – 4 per day 

Fruit – 2 per day

All weights of the fruits are of the edible components, i.e. no peel or inedible skin.

Milk/yogurt – 2 per day

Drinks: At least 2 litres of fluid per day, as described earlier on in this section. If you are having tea or coffee, you will need to use milk from the allowance above. 

Alternatives: The dietitian will be able to provide you with a comprehensive list of alternatives if you do not like some of the listed foods. If you wish to have the vegetarian option, please ask your dietitian.  

Seasonings/flavourings/additions: You may use any fresh or dried herbs or spices (including chilli) to flavour your meals.

Do not use any oil, butter, spread/margarine, cream or ready-made sauces (including salad dressings, mayonnaise & salad cream).  

You can of course make your own sauces using allowances above. You may also use up to 100ml daily of any type of vinegar. You may use up to 5 sprays of 1kcal per spray oil per meal if required. 

Sample plan 

We have created a sample plan for three days to show how you might put your allowances together. 

Option 3: Milk or meal replacement drinks with solid food

This plan consists of meal replacement shakes or milk and some food which you can incorporate into your day as you wish. If you do not eat meat or fish, a vegetarian option is available – please ask your dietitian in your preoperative appointment for a copy of this.  

This plan involves less weighing and measuring than Option 2, yet still allows some solid food unlike Option 1. As such, you may find it easier and more practical to follow. 

1. Milk or meal replacement drinks

Firstly, decide what milk or meal replacements you are going to have each day.  

Table 3 

Please make up the meal replacements as instructed by the manufacturer.  

2. Solid food

Then choose what food you are going to have each day. The table below shows how many portions of each food group you are allowed per day. 

Please refer to option 2 earlier in this section for the suitable foods in each group. 

If you prefer to follow the vegetarian option, there are two ways you can do this. You can exclude the milk/yogurt portion and have the following portions of each food group per day:  

Or you can exclude the carbohydrate and fruit portions and have the following portions of each food group per day: 

Please ask your dietitian for the list of vegetarian foods.  

If there are any foods not listed that you would like to include, please mention this to the dietitian. If nutritional information for the food/product is available, they can work out the portion size in grammes. 

Drinks: At least 2 litres of fluid as described earlier on in this section. If you are having tea or coffee, you will need to use milk from the allowance above. 

Alternatives: The dietitian will be able to provide you with a comprehensive list of alternatives if you do not like some of the listed foods. If you wish to have the vegetarian option, please ask your dietitian.  

Seasonings/flavourings/additions: You may use any fresh or dried herbs or spices (including chilli) to flavour your meals. 

Do not use any oil, butter, spread/margarine, cream or ready-made sauces (including salad dressings, mayonnaise and salad cream). You can of course make your own sauces using allowances above. You may also use up to 100ml daily of any type of vinegar. You may use up to 5 sprays of 1kcal per spray oil per meal if required. 

All the information above is correct at time of production.