Bariatric Surgery

Gastric Sleeve (Sleeve Gastrectomy)

A sleeve gastrectomy removes about 80% of the stomach, leaving a narrow tube. It is now the most commonly performed bariatric operation worldwide because it is technically simpler than a bypass, leaves the intestine untouched, and produces substantial, durable weight loss.

What is a gastric sleeve?

The surgeon removes the outer, expandable part of the stomach and leaves a narrow tube roughly the width of a banana. The stomach that remains holds far less food, so you feel full quickly and stay full longer.

Restriction is only part of how it works. The removed section produces most of the body's ghrelin, the hormone that drives hunger, so appetite itself typically falls sharply in the first year. That hormonal effect is why the operation outperforms dieting rather than simply enforcing it.

How it compares with a bypass

Simpler operation

One staple line and no intestinal connections, so the operation is shorter and there is no risk of internal hernia. This matters most in patients with a very high BMI or significant heart and lung disease.

Fewer nutritional problems

Because food still passes through the whole intestine, absorption is largely preserved. Supplements are still required for life, but severe deficiency is less common than after a bypass.

Less weight loss on average

Typically 50–60% of excess weight versus 60–70% after a bypass, and a somewhat higher rate of regain after five years. For many patients the difference is acceptable; for those with a very high BMI it may not be.

Reflux is the deciding factor

A sleeve can cause or worsen acid reflux, and in a minority it becomes severe enough to need conversion to a bypass. If you already have significant heartburn or a hiatus hernia, a bypass is usually the better operation — this single question changes the recommendation more than any other.

Who is a good candidate?

BMI of 40 or above, or 35–40 with an obesity-related disease
No significant acid reflux or hiatus hernia — the main reason to choose a bypass instead
Very high BMI or serious heart and lung disease, where a shorter operation is safer
Preference to keep the intestine intact, for example if future endoscopy of the bile duct is likely
Willing to take vitamin supplements and attend follow-up for life
No untreated eating disorder or active substance misuse
Able to complete the pre-operative liver-shrinking diet

Preparation

Upper endoscopy to look for reflux damage, hiatus hernia or Helicobacter infection — this can change the recommended operation
Abdominal ultrasound for gallstones, which often become symptomatic during rapid weight loss
Blood tests including vitamin and iron levels, thyroid function and HbA1c
Screening for obstructive sleep apnoea, which is common and affects anaesthesia
Cardiology and anaesthetic assessment appropriate to your BMI
Dietitian and psychology review — both are part of proper selection, not formalities
A two-week low-calorie liver-shrinking diet immediately before surgery

How the operation is performed

The operation is laparoscopic, through four or five incisions of about a centimetre. The surgeon frees the outer curve of the stomach, passes a calibration tube down to define the width of the sleeve, and divides the stomach along it with a stapler, removing the larger portion entirely.

The staple line is reinforced or oversewn, and a leak test is performed on the table by instilling dye or air. If a hiatus hernia is found, it is repaired at the same time — leaving it is a common cause of severe reflux afterwards.

Anaesthesia, duration and hospital stay

Anaesthesia: general, in a hospital with intensive care available
Operating time: 45–90 minutes
Hospital stay: 3 nights, with a leak test and imaging before discharge
Stay in the country: 7–10 days, so any early leak is detected while you are still here
Walking from the evening of surgery; clot prophylaxis throughout
Time off work: 2–3 weeks for desk work, longer for physical jobs
No lifting over 5 kg for four weeks

The diet stages after surgery

Week 1: clear liquids

Water, broth and sugar-free drinks in small, frequent sips. The single most important task is drinking enough — dehydration is the commonest reason patients are readmitted in the first fortnight.

Weeks 2–3: pureed food

Smooth, protein-first purees in portions of a few tablespoons. Protein comes before everything else at every meal, because muscle is what you lose if intake is inadequate.

Weeks 4–6: soft food

Soft solids, chewed thoroughly, still protein-first. Eating too fast or drinking with meals causes pain and vomiting — the two habits that most often derail this stage.

From week 6: normal texture

Regular food in small portions, three meals a day, protein first, no drinking for 30 minutes either side of eating. Supplements start and continue for life. Most weight is lost in the first 12–18 months.

Results and long-term outcome

Most patients lose 50–60% of their excess weight, the majority of it within the first 12 to 18 months. Type 2 diabetes improves in a large proportion and resolves in many, and sleep apnoea, blood pressure and joint pain usually improve alongside.

Some regain after two to five years is normal and expected; substantial regain usually reflects grazing, high-calorie liquids or loss of follow-up rather than a failed operation. A minority need conversion to a bypass, most often because of intractable reflux rather than weight.

Risks and complications

Staple-line leak — the most serious early complication, typically appearing in the first week with fever, fast heart rate or shoulder-tip pain; needs immediate treatment
Bleeding from the staple line, occasionally requiring transfusion or reoperation
Blood clots in the legs or lungs, reduced by early walking and prophylaxis
New or worsened acid reflux, sometimes severe enough to need conversion to a bypass
Narrowing (stricture) of the sleeve, causing vomiting and needing endoscopic dilatation
Nutritional deficiencies — iron, B12, vitamin D and thiamine — if supplements are not taken
Gallstones during rapid weight loss, sometimes needing gallbladder removal
Hair thinning, fatigue and mood changes in the first six months as intake falls

Cost and what should be included

The single biggest difference between a cheap package and a proper one is the length of hospital stay and whether the pre-operative work-up is included. A quote covering only the operation and one night is not a bariatric programme — it is an operation without the checks that make it safe.

Named surgeon's fee and their annual bariatric case volume
The full pre-operative work-up: endoscopy, ultrasound, bloods, sleep study, cardiology, dietitian and psychology
Anaesthesia and the anaesthetist's fee
Staplers and reload cartridges, by brand and number
Three nights in hospital with a leak test and imaging before discharge
Clot prophylaxis and post-operative medication
The written follow-up plan: which reviews, with whom, and for how long

Know the warning signs of a leak before you fly

A staple-line leak usually appears in the first week and is treatable when caught early. Fever, a heart rate above 120, worsening abdominal or left shoulder pain, or feeling suddenly and inexplicably unwell all mean going to hospital the same hour — not waiting to see. Ask for a 24-hour contact number and a named hospital to attend if you are already home.

Frequently asked questions

Will I be able to eat normally again?

You will eat normal food, in much smaller portions, and permanently. Most patients settle into three small meals a day and find that a quarter of their old portion is enough. Fizzy drinks, large volumes of liquid with meals and very sugary foods remain uncomfortable for most people long term.

Can a sleeve be reversed?

No. The removed part of the stomach is taken out of the body and cannot be put back. It can, however, be converted to a gastric bypass if severe reflux develops or weight loss is inadequate — that is a second operation with its own risks, not an undo button.

Why is a three-night stay necessary?

Because a staple-line leak typically declares itself between day two and day five, and it is far safer to be in hospital when it does. Packages that discharge you after one night are shifting that risk onto you and your hotel room. This is the part of the quote worth paying for.

Do I still need vitamins if I keep the whole intestine?

Yes, for life. Absorption is better preserved than after a bypass, but you are eating a fraction of your previous volume and the stomach produces less acid and intrinsic factor, both of which are needed for iron and vitamin B12. Deficiency develops silently over years and is entirely preventable with supplements and annual blood tests.

Have your case reviewed before you decide anything

Send your photographs and medical history. A board-certified surgeon reviews them and comes back with an honest assessment of what is achievable, which technique suits you, and an itemised written quote — before any money changes hands.

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This page provides general information about this procedure; it is not medical advice, a diagnosis, or a treatment recommendation. Capital Oncology Group is a care-coordination service and not a medical provider. All procedures are performed by independent, accredited hospitals and licensed physicians, and the decision to operate must be made by a qualified surgeon after examining you individually.