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Information for patients who can have food in their ‘pre-op’ diet
What is this information about?
This information gives you advice about how to follow the diet that you need to be on before your operation (your ‘pre-operative’ or ‘pre-op’ diet).
It explains:
- what the diet is
- when and why you must follow the diet
- what could happen if you do not follow the diet
- what you can have on the night before and on the day of your operation
- what happens if you have diabetes and need to follow the diet
- what side-effects you may get from being on the diet
- what types of foods and what portion sizes you can have on the diet.
Why have I been given this information?
You have been given this information because you are due to have an operation. It will help you to know what to expect from the diet that you must follow before your operation.
Following the advice can:
- help to make sure that your operation goes as well and as safely as possible
- help you to recover as soon as possible.
What is a pre-op diet?
A pre-op diet is a diet low in calories and carbohydrates (carbs).
Why must I follow the pre-operative diet?
It is important to follow the diet as it:
- makes your operation safer and more likely to be a success. The diet makes your liver smaller because you are having less calories and carbohydrates. This is important as it means:
- it is easier for the person doing your operation to reach your stomach, work around your liver, and do the operation safely
- it is less likely that your liver might be damaged during your operation.
- gives you enough nutrition to keep you well
Is the diet aimed at making me lose weight?
No. The main purpose of the diet is to make your liver smaller, but it is likely that you will lose weight while you are on it.
How long do I need to follow the diet for?
You must follow this diet for two weeks before your operation surgery, unless one of our team advise you otherwise.
Can I still have my operation if I do not follow the diet?
If you do not follow the diet, it is likely that your liver may be too large for us to do your operation safely. You cannot have your operation if your liver is too large.
What diet instructions must I follow from midnight the night before my surgery and on the day of my operation?
- From midnight on the night before your surgery you can drink clear fluids. For example, water, black tea, black coffee, no-added-sugar squash.
- On the day of your operation from either 6.30am or 11.30am (this depends on the time of your operation) you will not be able to eat or drink anything (you will be ‘nil by mouth’).
What happens if I am on the pre-op diet and I have diabetes?
You will only be having 120g of carbohydrate a day while you are on the pre-op diet. This means some of your diabetes medication may need to change.
At your pre-op appointment, the nurse will tell you about any changes to your diabetes medications and insulin dose.
If you take insulin or oral medications that can cause low blood sugar (hypoglycaemia), you need to check your blood sugar levels at least four times a day.
What side effects might I have because I am on the pre-op diet?
- Diarrhoea (runny poo)
If you have diarrhoea, you could take loperamide (Imodium) medication which you can get from a pharmacy. If you need advice, please contact the bariatric team.
- Constipation (difficulty pooing or very hard poos)
We recommend you take milk of magnesia, Laxido, senna, or Movicol to relieve constipation.
Do not
- arrive for your surgery constipated. Contact your pre op team if you are constipated close to the day of your operation.
Food Options
| Choose one | With (maximum portion size of one tea-plate) | |
| Breakfast Choose 1 per meal | 2 medium eggs 2 grilled bacon rashers 150g soya yogurt 4 slices Quorn bacon | Grilled tomatoes, boiled mushrooms or both. |
| Lunch Choose 1 per meal | 100g of oily fish. For example, tuna, salmon or mackerel. 100g of meat. For example, ham, chicken, turkey or minced meat. 150g of Quorn 150g of tempeh | Green salad (lettuce, cucumber, pepper, onion, tomato) with low calorie salad dressing OR Green vegetables (Not allowed: peas, potatoes, carrots, parsnips, sweetcorn or beetroot) |
| Tea Choose 1 per meal | 100g of oily fish. For example, tuna, salmon or mackerel. 100g of meat. For example, ham, chicken, turkey or minced meat. 200g (8oz) of tofu | Salad (as above) OR Vegetables (as above) Gravy made with Instant gravy granules is allowed. |
| Snacks Choose 3 per day | 1 pot (150g) low sugar Greek or natural yogurt 1 handful (45g) of raspberries or blueberries 1 mini sausage salami (10g) 25g plain nuts 200ml semi-skimmed or skimmed milk 25g cheese. If you are vegan, have 4 snacks a day. Make sure dairy alternatives are fortified with calcium. | |
| Drinks (fluids) | A minimum of 2 litres a day made up of the following: black tea (no sugar) black coffee (no sugar) herbal tea water no-added-sugar squash Bovril sugar-free jelly Not allowed: fizzy drinks or alcohol | |
Be aware,
all weights given are for foods before they are cooked.
Low calorie oil spray or 1 teaspoon of cooking oil daily is allowed.
Who can I contact if I need further information or advice after I have read this information?
Contact the bariatric surgery team:
Bariatric Surgery Service, St Richard’s Hospital.
St Richard’s Hospital.
01243 831655
This leaflet is intended for patients receiving care in St. Richard’s and Southlands.
The information in this leaflet is for guidance purposes only and is in no way intended to replace professional clinical advice by a qualified practitioner.
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