Gastric sleeve (sleeve gastrectomy)

What is a gastric sleeve?

A gastric sleeve removes about two-thirds to three-quarters of the stomach, leaving a narrow, banana-shaped tube. The removed part is taken out of the body, so this operation is not reversible. With a much smaller stomach you feel full after a small amount of food, and changes in gut hormones reduce appetite.

Unlike a gastric bypass, the bowel is not rerouted, so it is a somewhat simpler operation and absorbs nutrients more normally. However, you still absorb fewer vitamins and minerals than before, so you need supplements and blood tests for life. It can worsen or cause acid reflux, which is an important consideration.

A gastric sleeve is major, permanent surgery and a lifelong commitment, not a quick fix. Good results depend on permanent changes to how you eat, taking supplements for life, and ongoing follow-up; without these, weight can be regained.

Types & techniques

There isn't one single operation. The right approach depends on you — which is something to discuss with your surgeon.

Options at a glance

These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.

Preparing for your surgery

• Have a full assessment by a bariatric team, including a dietitian and often a psychologist, with clear discussion of all the options.
• Understand the eligibility criteria, usually a high BMI, often with weight-related illness, and previous attempts at weight loss.
• Tell the team about acid reflux, as a sleeve can make this worse and may affect which operation is best for you.
• Follow the pre-surgery diet (often a 'liver-shrinking' diet) exactly, as it makes the operation safer.
• Stop smoking, and tell the team all your medicines and supplements; some need stopping or changing.
• Plan for lifelong supplements, blood tests and follow-up, and arrange around 2–4 weeks off work and help at home.
• Discuss contraception, as pregnancy is usually advised against for 12–18 months after surgery.

What happens

The operation is usually done by keyhole surgery under general anaesthetic, often taking around one to two hours. The surgeon uses a stapling device to remove most of the stomach along a line, leaving a narrow tube (the sleeve). The removed portion is taken out through one of the small cuts. The staple line is checked for bleeding or leaks.

Most people stay in hospital for one to three nights. You start on fluids, then move through puréed and soft foods over several weeks before small, balanced solid meals. Lifelong supplements are started after surgery, and you are encouraged to move early to reduce the risk of blood clots.

Is this operation right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

Anaesthetic choices

The safest option depends on the operation, your health, the facility and your surgeon/anaesthetist. Ask what is planned and why.

A gastric sleeve is major, permanent surgery. The most feared early complication is a leak from the staple line, which is uncommon but can be very serious, along with blood clots. A particular long-term issue is reflux: a sleeve can cause or worsen heartburn, sometimes needing lifelong medication or even conversion to a bypass, and long-standing reflux can lead to Barrett's oesophagus. You also need lifelong supplements and blood tests. Ask your surgeon how many sleeves they do each year and what their leak, complication and reoperation rates are.

Published figures to discuss

A gastric sleeve is effective but carries the risks of major surgery plus lifelong nutritional considerations and a notable risk of reflux. Reported rates vary with the patient's health, the surgeon and the centre, and weight loss is an average, not a guarantee. The ranges below come from large bariatric series and outcome reviews and should be read cautiously.

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

Recovery — what to expect, and when

Recovery after a gastric sleeve takes a few weeks, with a staged diet and a gradual return to activity, followed by a lifelong routine of supplements, blood tests and follow-up.

• Tiredness and reduced appetite in the early weeks
• Temporary hair thinning during rapid weight loss
• Getting used to very small portions and eating slowly
• Some reflux or heartburn, which may need medication
• Changes in bowel habit as your body adjusts

Aftercare

• Follow the staged diet (fluids, puréed, soft, then small solid meals) exactly as advised.
• Take your prescribed vitamin and mineral supplements every day, for life.
• Eat small amounts slowly, chew well, and keep well hydrated between meals.
• Take acid-reducing medicine as advised, as reflux is common after a sleeve.
• Avoid smoking and, unless advised otherwise, anti-inflammatory painkillers, which raise ulcer risk.
• Attend all follow-up appointments and blood tests to check your nutrition.
• Keep the team's contact details and know who to call for severe pain, vomiting, fever or signs of a clot.

• Staged diet plan understood and suitable foods prepared
• Lifelong vitamin and mineral supplements obtained
• Acid-reducing medicine collected if prescribed
• Around 2–4 weeks off work and help at home arranged
• Follow-up appointments and blood tests booked
• Contraception discussed (avoid pregnancy for 12–18 months)
• Team and out-of-hours contact numbers saved

Scars and how they heal

Keyhole surgery leaves a few small scars on the tummy, which usually fade over months. If open surgery is needed, there is a longer scar that takes longer to settle. After major weight loss, some people develop loose, excess skin, and removal of this is not always available on the NHS.

⚠ Get urgent help if…

• Severe or worsening tummy or chest pain
• A fast heartbeat, fever or feeling very unwell (possible leak or infection)
• Persistent vomiting or being unable to keep fluids down
• Calf pain or swelling, or sudden breathlessness or chest pain (possible blood clot)
• Vomiting blood, or black, tarry stools
• Severe or persistent heartburn or difficulty swallowing
• New confusion, severe weakness, unsteadiness or vision changes (possible thiamine deficiency)

Who to contact: your surgeon or clinic first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your surgeon gives you.

Results & realistic expectations

A gastric sleeve usually produces substantial weight loss over one to two years and often improves or resolves type 2 diabetes, high blood pressure and sleep apnoea. The smaller stomach and hormone changes reduce appetite, but the operation works alongside your eating and lifestyle, not instead of them.

It is not a cure for obesity. Some weight regain over the years is common, and reflux can become a long-term problem for some people. Lifelong supplements and follow-up are needed to stay well. The best results come from combining the surgery with permanent diet change, regular activity, supplements and ongoing support.

Most people keep off a large part of the weight long term, though some regain occurs over the years and a minority need revision surgery, most often a conversion to a gastric bypass for severe reflux or weight regain. Because the stomach is removed, the sleeve itself is permanent. Lifelong attention to nutrition is essential, and ongoing follow-up helps maintain weight loss, manage reflux and keep your nutrition safe.

Combining with other procedures

A gastric sleeve is part of a wider pathway with dietitian and behavioural support. A hiatus hernia may be repaired at the same time to reduce reflux. If reflux is severe or weight is regained later, the sleeve can sometimes be converted to a gastric bypass. Gallbladder removal is occasionally needed if gallstones develop, and some people later consider surgery to remove excess skin.

Follow-up & long-term care

You will need regular follow-up and blood tests, continuing for life, to monitor weight, reflux, nutrition and any complications. Through NHS weight-management services, lifelong follow-up is usually offered; privately, confirm exactly what follow-up, blood monitoring and aftercare are included, for how long, and who provides them if you move your care.

• Lifelong daily vitamin and mineral supplements
• Regular (at least annual) blood tests to check for deficiencies
• Lifelong follow-up with a bariatric team or appropriate service
• Acid-reducing medication and monitoring for reflux where needed
• Small, balanced, protein-focused meals and good hydration
• Prompt review for persistent vomiting, severe reflux or new symptoms

Revision and secondary surgery reality

• A minority need further surgery, most often conversion to a gastric bypass for severe reflux or weight regain.
• The sleeve itself is permanent, as most of the stomach is removed.
• Strictures or leaks can occasionally need procedures such as stretching or further surgery.
• Lifelong nutritional follow-up is part of the deal, not an optional extra.

Ask your surgeon for their own revision rate, what counts as a revision, and what is included in the written aftercare policy.

What good aftercare looks like

• Lifelong follow-up and at least annual blood tests with a clear supplement plan.
• A named contact and clear warning signs for leaks, clots, vomiting and severe reflux.
• Monitoring and treatment of reflux, including review if it becomes severe.
• Dietitian and behavioural support to sustain weight loss and protect nutrition.
• A plan for managing late complications, including possible conversion surgery.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

• The surgeon's and anaesthetist's fees and the theatre or facility fee
• Length of hospital stay and level of post-operative care
• Dietitian and, where needed, psychology input before and after surgery
• Lifelong vitamin and mineral supplements and regular blood tests
• Acid-reducing medication and monitoring for reflux
• Follow-up appointments and any imaging or endoscopy needed
• Management of complications or revision surgery, which may add significant cost

• The surgeon's, anaesthetist's and facility fees and expected length of stay
• Dietitian and psychology input before and after surgery
• How many follow-up visits and blood tests are included, and for how long
• Whether lifelong nutritional monitoring and supplements are covered or your responsibility
• Cancellation policy
• What happens, and what it costs, if you need readmission, revision or treatment for reflux
• Who provides your follow-up if you move your care elsewhere

On the NHS? Gastric sleeve surgery is available on the NHS for people meeting strict criteria after specialist assessment; private surgery is mainly chosen for speed or choice and should include lifelong follow-up and nutritional monitoring.

You're entitled to your total cost in writing — including aftercare and any revision — before you decide.

Consent traps and marketing red flags

These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.

Choosing a surgeon safely

• Check your surgeon is on the GMC Specialist Register for this area.
• Make sure they practise at a CQC-registered location, and look for membership of bodies like BAAPS or BAPRAS.
• You're entitled to a two-stage consent process with time to reflect (a cooling-off period). The surgeon who will operate must consent you — not a salesperson.
• Be wary of pressure: time-limited offers, discounts or deposits taken before you've had time to think are red flags, not bargains.
• You're entitled to your total cost in writing — including aftercare and any revision — before you decide.

How Vuemedics verifies every consultant →

Take this to your consultation. A good surgeon will welcome every one of these.

• Given my health and any reflux, would a sleeve, bypass or band suit me best, and why?
• How many gastric sleeves do you do each year, and what are your leak and complication rates?
• What are my personal risks of a leak, blood clot, reflux or needing further surgery?
• Exactly which supplements and blood tests will I need, and for how long?
• How will reflux be monitored and managed, and what if it becomes severe?
• What follow-up is included, and who looks after me if I move my care?
• Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
• Will you be the surgeon who carries out my operation, and who looks after me afterwards?
• What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
• What does a realistic result look like — and what can this operation not achieve?
• What are my options, including waiting, doing nothing for now, or choosing a different approach?
• Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
• What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Find a verified surgeon for gastric sleeve (sleeve gastrectomy)

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How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: NHS — Weight loss surgery NHS — Weight loss surgery: risks BOMSS — Patient information: managing obesity and surgery BOMSS — Guidelines on biochemical monitoring and micronutrient replacement after bariatric surgery (2020) Prevalence of and risk factors for Barrett's oesophagus after sleeve gastrectomy — PMC Long-term effectiveness, outcomes and complications of bariatric surgery — PMC The new onset of GERD after sleeve gastrectomy: systematic review — PMC

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.