Sleeve gastrectomy: what is it, and who is it for?

What is sleeve gastrectomy?

In a sleeve gastrectomy, a portion of the stomach is removed, leaving a narrow “sleeve.” This reduces the amount of food the stomach can hold and affects hunger-related hormones. It is typically performed laparoscopically at established hospitals.

Sleeve gastrectomy is permanent — the removed portion of the stomach cannot be restored. It is a significant operation under general anesthesia, and it requires lasting changes to how you eat and how your health is monitored.

Why sleeve gastrectomy is commonly considered

Sleeve gastrectomy is often considered because it is technically simpler than gastric bypass and does not bypass the small intestine. Food still passes through the normal gastrointestinal route, which may reduce some concerns related to malabsorption compared with bypass procedures.

However, sleeve gastrectomy is still a major metabolic operation. It changes stomach volume, appetite regulation, eating behavior, and long-term nutritional requirements. Some patients may still develop deficiencies in nutrients such as iron, vitamin B12, folate, vitamin D, or zinc, so long-term follow-up is necessary. Compare the two procedures in our gastric bypass guide.

Who may be considered?

Candidacy is determined by specialist evaluation, generally taking into account BMI, obesity-related conditions (such as type 2 diabetes, hypertension, sleep apnea, or fatty liver disease), previous weight-loss attempts, and overall surgical fitness.

For Asian patients, bariatric surgery may be considered at lower BMI levels than traditional Western criteria. The Korean (KSMBS) guideline states that bariatric surgery may be recommended in Asia for patients with BMI ≥ 35 kg/m², or ≥ 30 kg/m² with obesity-related comorbidities.

Candidate selection should also consider type 2 diabetes, hypertension, dyslipidemia, sleep apnea, fatty liver disease, gastroesophageal reflux, previous abdominal surgery, nutritional status, and psychological readiness. These figures are a starting point for discussion, not an entitlement to surgery.

When sleeve gastrectomy may not be ideal

Sleeve gastrectomy may not be appropriate for every patient. The Korean guideline notes that Barrett’s esophagus is a contraindication for sleeve gastrectomy. Patients with significant reflux symptoms, hiatal hernia, or abnormal endoscopic findings may need careful evaluation before deciding on this procedure — and may be better suited to gastric bypass.

For international patients considering surgery in Korea, upper gastrointestinal endoscopy is especially important. Korea has a strong clinical emphasis on gastric disease screening, and the KSMBS guideline highlights the need for preoperative upper gastrointestinal endoscopy and Helicobacter pylori testing in the Korean setting.

What should be reviewed before treatment

• Complete medical history and current medications, including any GLP-1 use
• Laboratory and metabolic testing
• Endoscopic evaluation of the stomach and esophagus where indicated
• Anesthesia risk assessment
• Nutritional and, where appropriate, psychological readiness

Parts of this begin remotely through document review before you travel, and are completed in person in Korea. The pre-operative program is where the real treatment decision is made — it can confirm, change, delay, or rule out the planned procedure.

Potential benefits

For eligible patients, sleeve gastrectomy can offer significant and durable weight loss, and it can improve obesity-related conditions such as type 2 diabetes in selected patients. Results vary between individuals, and no outcome can be guaranteed.

See how surgery compares with medication in our GLP-1 vs bariatric surgery guide.

Possible risks

As with any major surgery, risks include bleeding, infection, leakage at the staple line, blood clots, and anesthesia-related complications. Longer term, some patients experience reflux, nutritional deficiencies, or weight regain.

Serious complications at experienced centers are uncommon but never zero. Your surgical team will explain the risks specific to your procedure and health profile before you consent to anything.

Recovery and lifelong follow-up

Recovery follows a structured progression — from liquids to soft foods to a stable long-term diet — together with supplementation, activity guidance, and scheduled follow-up. Lifelong vitamin and mineral supplementation is commonly required, along with scheduled blood testing.

Because most recovery happens at home, your discharge plan should specify your diet and supplementation schedule, which follow-up checks and blood tests you need and when, what a local doctor can manage, and warning signs — such as persistent vomiting, fever, or worsening abdominal pain — that require prompt local care. Read more on safety and follow-up.

Key questions to ask

Before choosing sleeve gastrectomy in Korea, it helps to ask:

• Is sleeve gastrectomy suitable for my BMI and obesity-related diseases?
• Do I have reflux, Barrett’s esophagus, hiatal hernia, or gastric disease?
• What preoperative tests are required?
• How will my nutrition be monitored after surgery?
• What follow-up plan is available after I return home?
• What is the estimated cost as an international self-paid patient?

See the cost guide for how estimates are prepared, and the bariatric surgery for type 2 diabetes guide if diabetes is part of your picture.