Liver reduction diet before surgery
The liver reduction diet is a short pre-op eating plan that your hospital prescribes, usually for two weeks. It supplies around 800–1,000 kcal and under 100g of carbohydrate each day. It shrinks the liver so your surgeon can move it aside during keyhole surgery. Your hospital team sets the version and the length.
This guide draws on published NHS dietetics leaflets, including those from Chelsea and Westminster and from Oxford University Hospitals. Always follow your own hospital’s instructions. If your hospital leaflet says something different to this page, follow your leaflet.
The clinical and regulatory references on this page were last checked on 8 October 2026.
At a glance
- The daily targets.
- About 800–1,000 kcal, under 100g of carbohydrate, low fat and high protein. Drink plenty of fluid (2 to 2.5 litres a day) and no alcohol.
- The length.
- Usually two weeks. Often four weeks if your BMI is over 50, or if you have type 2 diabetes, sleep apnoea or a fatty liver. Your team confirms it.
- The reason.
- A smaller, softer liver gives the surgeon room to work during keyhole surgery. It reduces the chance of the operation being converted to open surgery, or cancelled on the day.
- Three versions.
- Hospitals use a food-based, a milk-based or a meal replacement version. Follow the one your leaflet offers and stay on it.
- Medication.
- If you take insulin, gliclazide, other diabetes tablets, or blood pressure medicines, speak to your diabetes or GP team before you start. Doses often need reviewing first.
- It ends at surgery.
- You then move on to the post-op diet stages your team sets. The liver reduction diet is not a long-term way of eating.
What is a liver reduction diet?
A liver reduction diet, also called a liver shrinkage diet or LRD, is a short eating plan that is low in calories, carbohydrate and fat. Most hospitals ask bariatric surgery patients to follow it for two to four weeks before their operation. The daily targets are roughly 800–1,000 kcal and under 100g of carbohydrate, with adequate protein.
Many NHS trusts publish their own version, and the exact numbers shift a little between them. Chelsea and Westminster, Oxford University Hospitals and other trusts all set broadly the same calorie and carbohydrate targets, but each gets you there in a slightly different way. Some give you a food-based plan. Some offer a milk-only plan. Some use a meal replacement plan. The job is identical in each case: cut calories and carbohydrate hard, for a short time, under the eye of a dietitian or your surgical team.
The diet is normally prescribed before bariatric surgery — a sleeve gastrectomy, gastric bypass or band. A number of hospitals use something similar before other upper-abdominal keyhole procedures where the liver can get in the surgeon’s way. Oxford University Hospitals’ version, for instance, is written by its liver and gallbladder (hepatobiliary) dietitians.
Why do I need to shrink my liver before surgery?
Your liver sits over the top of your stomach. If it is large or fatty, it blocks the surgeon’s view and makes keyhole bariatric surgery harder, longer or impossible. Cutting carbohydrate and calories for two to four weeks drains the glycogen stored in the liver and the water held with it, so the liver gets smaller and softer.
The NHS leaflets put it like this. Your liver stores sugar as glycogen, and each gram of glycogen holds roughly three to four grams of water. When you eat much less carbohydrate for a sustained stretch, the glycogen stores empty and the water goes with them, so the liver shrinks. A smaller, softer liver is one the surgeon can lift safely aside during keyhole surgery.
If the liver has not shrunk enough by the day of surgery, the team has two options. They can convert the keyhole procedure to open surgery, which is a bigger operation with a longer recovery. Or they can cancel and rebook you. That is why the diet matters so much: the operation hinges on it. You will lose some weight during the diet as well, but weight loss is not the point. Liver size is.
How long is the liver shrinking diet?
A liver shrinking diet usually runs for two weeks. Four weeks is more common if your BMI is over 50, or if you have type 2 diabetes, sleep apnoea or a known fatty liver. A few trusts prescribe longer. Your surgical team decides how long you stay on it.
Follow it right up to the day of surgery, starting on the date your hospital gives you. Do not rely on an estimate you have pieced together online.
What can I eat? The three versions hospitals use
Hospitals use three versions of the liver reduction diet: a food-based plan, a milk-based plan, or a meal replacement plan built on shakes and soups. All three aim at the same daily targets of 800–1,000 kcal and under 100g of carbohydrate. Your leaflet will offer one or more of them. Pick one and follow it fully.
The food-based plan is made up of small, measured meals. A typical day includes:
- a small, measured portion of starchy carbohydrate — for example one Weetabix or a slice of bread at breakfast
- lean protein and plenty of non-starchy vegetables at lunch and dinner
- low-fat dairy and two portions of fruit
It takes planning and weighing, and your leaflet tells you exactly what a portion is. The usual exclusions are sugar, sweets, cakes, crisps, fried food, takeaways, creamy sauces and alcohol.
The milk-based plan uses around 3 to 3½ pints (about 2 litres) of skimmed or semi-skimmed milk a day, depending on your trust. You split it across the day and, if your leaflet includes them, add low-fat yoghurt, a daily multivitamin, and water or no-added-sugar squash. It is the simplest to shop for and the most repetitive.
The meal replacement plan comes in two forms.
- All meals replaced. Some trusts swap every meal for four or five shakes or meal bars a day, made to a set formula. Some add a couple of bowls of vegetables on top.
- Some meals replaced. Others, such as Oxford University Hospitals, replace two meals with shakes and keep a small evening meal.
Either way, the product supplies most of the day’s calories, carbohydrate, protein and vitamins, so there is less to weigh or calculate. Several NHS leaflets use a branded bottled shake for this. The plan in the next section is the all-meals-replaced form, built from our own shakes and soups to hit the same daily targets.
Don’t mix versions within a day. If you are on the shake plan, do not add food on top. If you are on the milk plan, do not swap in shakes. Mixing changes the daily totals in ways the plan is not designed for. Some trusts do allow you to alternate whole days between two versions, so check your leaflet.
A 2-week liver reduction meal plan using Shake That Weight
Two of our milkshakes and two of our soups a day meet the NHS targets: 800–1,000 kcal, under 100g of carbohydrate, low fat and high protein. Each day of the plan below works out at about 850 kcal and 92–95g of carbohydrate. Week 2 repeats the same seven days.
Which products to use on this plan
- Shakes, made with 250ml skimmed milk: Vanilla, Chocolate, Strawberry, Café Latte and Chocolate Mint. Each one, as prepared, is 218–230 kcal, 25.4–26.7g carbohydrate, 3.2–4.1g fat and 20–21.6g protein. The carbohydrate figure includes the natural sugar in the milk. See our shakes.
- Soups, made with water: have one of each a day. See our soups.
- Cream of Pea: 200 kcal, 22g carbohydrate, 3.8g fat, 18g protein
- Vegetable: 203 kcal, 19.5g carbohydrate, 6.1g fat, 16.2g protein
Which to avoid on this plan
- Cherry Bakewell, Tropical and Chocolate Hazelnut shakes. They are higher in carbohydrate (26.5–29.7g) and lower in protein (13g) per serving. Four a day works out at about 106–119g of carbohydrate, which is above the under-100g target. See the vegan option below.
- Meal bars. They are higher in fat, so leave them out for these two weeks.
- Four shakes and no soup. Four of the milkshakes a day comes close to or over 100g of carbohydrate. Keep both soups in every day.
Example day: two shakes and two soups
Vanilla shake + Cream of Pea soup + Strawberry shake + Vegetable soup.
844 kcal · 93.2g carbohydrate · 16.7g fat · 74.7g protein
That hits every NHS target: 800–1,000 kcal, under 100g of carbohydrate, low fat and high protein.
7-day plan: two shakes and two soups a day
| Day | Breakfast | Lunch | Afternoon | Evening | kcal | Carbs (g) | Fat (g) | Protein (g) |
|---|---|---|---|---|---|---|---|---|
| 1 | Vanilla shake | Cream of Pea soup | Strawberry shake | Vegetable soup | 844 | 93.2 | 16.7 | 74.7 |
| 2 | Chocolate shake | Cream of Pea soup | Café Latte shake | Vegetable soup | 846 | 93.6 | 16.6 | 76.3 |
| 3 | Chocolate Mint shake | Cream of Pea soup | Vanilla shake | Vegetable soup | 856 | 93.2 | 17.6 | 75.8 |
| 4 | Strawberry shake | Cream of Pea soup | Chocolate shake | Vegetable soup | 846 | 93.6 | 16.6 | 75.8 |
| 5 | Café Latte shake | Cream of Pea soup | Chocolate Mint shake | Vegetable soup | 851 | 92.3 | 17.2 | 76.8 |
| 6 | Vanilla shake | Cream of Pea soup | Chocolate shake | Vegetable soup | 851 | 94.5 | 17.0 | 75.3 |
| 7 | Strawberry shake | Cream of Pea soup | Chocolate Mint shake | Vegetable soup | 851 | 92.3 | 17.2 | 76.3 |
Nutritionally complete at four a day. Four of our Total Plan shakes or soups a day give you the vitamins, minerals and protein a meal replacement plan is designed to supply for a short period. There is nothing to work out yourself, and your hospital team looks after the clinical side.
If your hospital sets limits per shake. Some trusts set a cap for each shake rather than for the day. Oxford University Hospitals, for example, replaces two meals with shakes of no more than 200 kcal and 15g of carbohydrate each. Each of our products is a complete meal in its own right, at about 200–230 kcal and 19.5–26.7g of carbohydrate, so none of them meets a per-shake limit set at that level. This plan fits a version where shakes and soups replace all your meals. If your leaflet sets per-shake limits, follow your leaflet, or show this plan to your dietitian.
Vegan option: the honest numbers. Our vegan shakes are Cherry Bakewell, Tropical and Chocolate Hazelnut. They are higher in carbohydrate than the shakes above.
| Vegan day, four shakes made with water | kcal | Carbs (g) | Fat (g) | Protein (g) |
|---|---|---|---|---|
| 4 × Chocolate Hazelnut shake | 800 | 106 | 14.4 | 52 |
| 4 × Cherry Bakewell or 4 × Tropical shake | 816 | 118.8 | 12.4 | 52 |
Our soups contain milk, so they cannot be used to pull a vegan day’s carbs down. The lowest-carb vegan day is four Chocolate Hazelnut shakes. That comes to about 800 kcal and 106g of carbohydrate, which is slightly above the NHS under-100g target. Show these numbers to your dietitian before you choose the vegan route. Your team can tell you whether about 106g of carbohydrate a day is acceptable for you, or whether you should use a different plan.
Fluids. Drink at least 2 to 2.5 litres of water, no-added-sugar squash, tea or coffee a day on top of your four products. Avoid all alcohol, including alcohol-free beer and wine. If your hospital’s version suggests a daily cup of stock or another salty drink, have it.
Dispatch and delivery. We dispatch orders for delivery the next working day, so your box arrives in time to start on the date your hospital gives you.
Before you start: medication and who shouldn’t follow it
If you take insulin, gliclazide or other diabetes tablets, or blood pressure medicines, speak to your diabetes or GP team before you start. The diet can lower your blood glucose and your blood pressure quickly, so doses often need reviewing before you cut calories. The liver reduction diet is also not suitable for everyone.
Diabetes medication. On insulin or tablets such as gliclazide, eating much less can send your blood glucose too low. If your dose has not been reviewed first, you could have a hypo. The NHS leaflets tell you to contact your diabetes team before you start, and to test your blood glucose more often during the diet. Dose decisions are for your team, not for us. If you take weight-loss injections or other GLP-1 medication, speak to your prescriber before you start as well. Read more about meal replacement shakes and type 2 diabetes.
Blood pressure medication. The Oxford University Hospitals leaflet notes that blood pressure medicines may need adjusting during the diet, and that you may need to check your blood pressure more often. Any changes go through your GP or hospital team, not through you alone.
Tell your pre-assessment team. Some hospitals give patients a carbohydrate drink before surgery. The Torbay and South Devon leaflet says patients on a liver reduction diet will not have it. Make sure your pre-assessment team knows you are on the diet.
Who should not follow a liver reduction diet. NHS guidance says the diet is not advised for:
- adolescents
- people who are pregnant or breastfeeding
- older people
- people with unstable heart or cerebrovascular disease
- people with kidney failure or severe liver failure
- people with acute psychiatric illness
If dieting or eating has been difficult for you in the past, say so. A dietitian can support you through it.
It is short-term only. Very low-calorie eating is a short-term measure. The liver reduction diet runs for two to four weeks and stops at surgery.
What to expect: side effects and tips
Expect to feel more tired than usual, especially in the first week while your body adjusts. Headaches, light-headedness, constipation, thirst, ketone breath and a metallic taste in your mouth are all common. Most of them ease within a few days. You will lose some weight, but the aim is a smaller liver, not a lower number on the scale.
Fluids. Drink at least 2 to 2.5 litres a day of water, no-added-sugar squash, tea or coffee. Avoid all alcohol, including alcohol-free beer and wine. The Oxford University Hospitals leaflet is explicit about that.
Constipation. Eating less food means less fibre, which can slow things down. Drinking plenty helps. If it does not settle, ask a pharmacist or your team about a suitable laxative or fibre supplement. The Chelsea and Westminster leaflet says not to use lactulose while you are on this diet.
Periods and fertility. Periods can change during the diet. If you have PCOS, you may become more fertile, so think about contraception. The Chelsea and Westminster leaflet makes both points.
Headaches and light-headedness. These often appear around day 2 as your carbohydrate intake drops, and they usually pass. If your team suggests a cup of stock or another salty drink, it can help. If headaches are severe, do not settle, or you feel faint, contact your team.
Blood glucose. If you take diabetes medication, test more often than usual and keep hypo treatment with you. Follow the hypo plan your diabetes team gave you.
Keep going. Most people find the first few days the hardest and feel it easing after that. The plan only runs for a short, defined window. Do not be tempted by a “last big meal” before surgery. The Oxford leaflet warns against it specifically, because it undoes the benefit of the diet. Follow your hospital’s fasting instructions for the hours before your operation.
After surgery
The liver reduction diet ends on the day of surgery. From there you move on to the post-op diet stages your bariatric team gives you. They usually run from fluids to puréed food, then soft food, and finally back to small normal meals. Your team leads that process.
Shake That Weight products are not a post-op bariatric diet. If your team wants you on protein shakes after surgery, use the ones they recommend.
<!– 11 FAQ — FAQPage JSON-LD is generated from these
Can I have Weetabix, bread or porridge on a liver shrinking diet?
Can I drink coffee or tea?
Can I use any meal replacement shake?
Is a liver shrinking diet the same for gallbladder removal?
What happens if I don’t follow the diet?
Can I mix shakes and food within the same day?
Can I use soups on the liver reduction diet?
How much weight will I lose on it?
Sources
- Chelsea and Westminster Hospital NHS Foundation Trust, Liver shrinkage diet for bariatric surgery.
- Oxford University Hospitals NHS Foundation Trust, Pre-operative Liver Shrinkage Diet for Surgery, OMI 114399, September 2025 (review September 2028).
- Shake That Weight product nutrition panels, as prepared (shakes with 250ml skimmed milk, soups with water), pulled from product meta on 8 October 2026.
Last reviewed: 8 October 2026.