Gastric sleeve surgery (sleeve gastrectomy) is an established bariatric procedure in which approximately 75-80% of the stomach is removed laparoscopically and the remaining portion is reshaped into a narrow, long tube. According to IFSO data, it is among the most frequently performed bariatric procedures worldwide.
Medically reviewed by Assoc. Prof. Dr. Hasan Abuoğlu · June 21, 2026
Gastric sleeve surgery, medically known as sleeve gastrectomy, is a laparoscopic bariatric procedure in which approximately 80% of the stomach is removed, leaving a narrow, banana-shaped tube. It is one of the most commonly performed weight-loss procedures worldwide. The operation works by both reducing stomach capacity and removing the region where hunger hormones are produced, creating lasting metabolic change.
Obesity is not simply a matter of excess weight; it is a chronic condition linked to type 2 diabetes, obstructive sleep apnea, hypertension, and cardiovascular disease. When lifestyle modification and medical therapy are not sufficient, sleeve gastrectomy is a clinically validated surgical option supported by international guidelines [1][2].
Sleeve gastrectomy works through two main mechanisms. The first is restriction: stomach capacity is reduced from approximately 1,500 mL to 100–150 mL, producing early satiety after small meals. The second is hormonal: the removed fundus is the primary site of ghrelin production, the hormone that signals hunger. Ghrelin levels drop significantly after surgery, reducing appetite.
At the same time, satiety hormones such as GLP-1 and PYY increase. This hormonal shift improves insulin sensitivity and produces beneficial effects on type 2 diabetes and metabolic syndrome. For this reason, sleeve gastrectomy is considered a metabolic procedure as well as a weight-loss intervention.
The procedure is performed through 4–5 small incisions (0.5–1 cm) in the abdominal wall; no large open incision is required. Using a camera and specialized instruments, the stomach is divided vertically along its greater curvature using a surgical stapler, and the removed portion is permanently excised. The staple line is secured with titanium staples and typically reinforced with an additional suture line to reduce leakage risk.
Average operating time is 60–90 minutes. The procedure is performed under general anesthesia, with a typical hospital stay of 3–4 days. Robotic surgery is offered in some centers and provides three-dimensional vision with enhanced precision, though laparoscopic sleeve gastrectomy remains the current standard in experienced hands.
According to the IFSO Global Registry, sleeve gastrectomy accounted for approximately 60% of all bariatric procedures performed worldwide in 2022 [1]. This reflects the method's widespread adoption and its position as the most common bariatric procedure globally, surpassing gastric bypass in volume. Türkiye is an internationally recognized destination in this field, with experienced centers and high surgical volume.
Sleeve gastrectomy is not suitable for every patient living with obesity. Candidacy is determined only after a comprehensive clinical evaluation by a qualified surgical team.
Current IFSO and ASMBS guidelines define the following indications [1][2]: adults with a body mass index (BMI) of 40 or above are primary candidates. Patients with a BMI between 35 and 40 are candidates if they have obesity-related conditions such as type 2 diabetes, obstructive sleep apnea, hypertension, severe joint disease, or non-alcoholic fatty liver disease.
The 2022 IFSO-ASMBS joint update expanded criteria to include patients with a BMI of 30–35 when uncontrolled type 2 diabetes is present [2]. The typical age range is 18–65, though carefully selected adolescents (with parental consent and multidisciplinary review) and older adults in good physical condition may also be considered following detailed assessment.
Certain conditions make sleeve gastrectomy inappropriate. Pregnancy and breastfeeding are absolute contraindications; pregnancy should be postponed for at least 12–18 months after surgery. In patients with severe treatment-resistant gastroesophageal reflux disease (GERD) or large hiatal hernia, gastric bypass may be preferred. Active peptic ulcer disease must be treated before surgery.
Untreated severe psychiatric illness, active eating disorders, and substance dependence are temporary contraindications. Endocrine causes of obesity such as Cushing's syndrome or untreated hypothyroidism must be addressed first. Preoperative endocrinology and psychiatry consultations are routine to identify these conditions.
If three or more of the following apply to you, a specialist consultation may be worthwhile:
Your BMI is above 35
You have been unable to achieve sustained weight loss for more than six months with diet and exercise
You have been diagnosed with type 2 diabetes or sleep apnea
Your weight limits your daily activities
You experience obesity-related joint problems
This list is not diagnostic; it is intended only as a starting point for considering professional evaluation.
A well-planned preparation period is the foundation of a successful procedure. The process typically spans 4–6 weeks and involves a multidisciplinary team.
The first consultation includes a detailed medical history: weight history, previous diet attempts, family history, current conditions, and medications. After physical examination, comprehensive preoperative testing is performed: complete blood count, liver and kidney function panels, HbA1c, lipid profile, thyroid function, vitamin B12 and D levels, EKG, chest X-ray, and upper abdominal imaging. Internal medicine and cardiology evaluations are routine.
Upper gastrointestinal endoscopy is mandatory to assess gastric mucosa, identify hiatal hernia, and screen for Helicobacter pylori. If H. pylori is positive, eradication therapy is completed before surgery. Psychological evaluation screens for eating disorders, and anesthesia consultation assesses cardiac and pulmonary risk.
A protein-focused liquid or low-carbohydrate diet begins 2–4 weeks before surgery. Its primary purpose is to reduce liver volume; the enlarged left lobe of the liver common in patients with obesity can obstruct laparoscopic visualization. This diet typically reduces liver volume by 15–20% and improves surgical safety.
Daily targets are typically 60–80 g of protein and 800–1,200 calories. Protein shakes, low-fat dairy, clear broth, and sugar-free beverages form the basis of the diet. Smoking and alcohol must be stopped during this period; smoking impairs wound healing and increases leak risk.
Oral intake stops 8–12 hours before surgery. You arrive at the hospital in the morning, antibiotic prophylaxis is administered, and deep vein thrombosis prevention measures — compression stockings and low-molecular-weight heparin — are initiated.
The operation lasts 60–90 minutes. After a brief recovery room observation, you are transferred to your room. Early mobilization — standing and short walks on the day of surgery — reduces thrombosis risk and helps bowel function return quickly.
Weight loss and metabolic improvement after sleeve gastrectomy follow a predictable curve. Understanding this curve is essential for realistic expectation management.
In international literature, weight loss is expressed as excess weight loss (EWL), the percentage of excess weight that has been shed [3]. During the first three months, average EWL is 25–30% — this is the most rapid phase. At six months EWL reaches approximately 50%. By the end of the first year, 60–70% EWL is typical, and the peak of 65–75% EWL is reached in the second year.
At the five-year mark, average EWL settles around 55–65%, with approximately 15–20% of patients experiencing meaningful weight regain [3]. For this reason, surgery should be viewed not as an endpoint but as the start of a lifelong pattern of nutrition and lifestyle discipline. Individual results vary based on age, starting BMI, sex, and patient adherence.
The effects of sleeve gastrectomy extend beyond weight loss. According to IFSO and ASMBS data, complete remission of type 2 diabetes occurs in approximately 60–65% of patients within the first two years [1][2]. Obstructive sleep apnea improves substantially in roughly 80% of patients, and CPAP dependence is often eliminated.
Hypertension improves or resolves in approximately 55% of cases, and dyslipidemia normalizes in about 70%. Women with polycystic ovary syndrome often experience improved menstrual regularity and fertility. These figures represent literature averages; individual response varies.
The first week involves hospital and home recovery. Short walks and light household activity begin between days 7 and 14. Return to desk-based work is typically possible by weeks 3–4; physically demanding jobs may require 6 weeks.
From the third month, low-impact exercise such as walking and swimming supports cardiovascular health. At six months, resistance training can be added — this is particularly important for preserving muscle mass during rapid weight loss. Pilates and light aerobic exercise improve flexibility and overall balance. Exercise programs should be designed with your surgeon and physiotherapist.
Like any surgical procedure, sleeve gastrectomy carries specific risks. Transparent discussion of these risks is the foundation of informed consent.
The most serious early complication is a staple-line leak, reported in 1–2% of cases in the international literature [3]. Early recognition is critical; postoperative tachycardia, fever, and severe abdominal pain are warning signs. Bleeding occurs in approximately 1% and is usually managed conservatively.
Superficial wound infection, deep vein thrombosis, and pulmonary embolism are other early complications. The need for early reoperation is less than 2%. In accredited centers, mortality rates reported in the literature are in the range of 0.1–0.3% [3].
The most common late issue is the development or worsening of gastroesophageal reflux disease (GERD), reported in 15–25% of cases [3]. For this reason, patients with severe preexisting reflux may be considered for alternative procedures. Narrowing of the sleeve (stricture) is rare and usually managed with endoscopic dilation.
Vitamin and mineral deficiencies require lifelong monitoring: B12, vitamin D, iron, and folate levels should be checked at least annually. After year five, approximately 20% of patients may experience meaningful weight regain, and revision surgery — typically conversion to gastric bypass — may be considered.
Key variables influencing complication rates include center experience, multidisciplinary team structure, and patient adherence. The literature consistently shows lower complication rates in high-volume bariatric centers [3].
Patient adherence to the preoperative liquid diet, smoking cessation, and the postoperative nutrition protocol directly affects risk. International accreditations such as IFSO Center of Excellence indicate that standardized protocols are in place.
Nutrition is the single most important factor determining long-term success after sleeve gastrectomy. The phased plan supports healing of the stomach while enabling healthy weight loss.
The first two weeks are fully liquid. Water, strained and fat-free broth, sugar-free herbal teas, and lactose-free milk are acceptable. Daily protein target is 25–30 g, often supported by protein shakes. Fluid intake of 8–10 cups (1.5–2 L) per day prevents dehydration.
Small sips, slowly consumed, are essential; rapid intake causes nausea and vomiting. Solids and liquids are not consumed at the same time — this rule is lifelong. Carbonated drinks, sugary beverages, and alcohol are strictly avoided.
From week three, purees and soft textures are introduced. Yogurt, cottage cheese, blended legume soups, soft-cooked fish, and egg whites are primary options. Portion size is typically 2–3 tablespoons. Fruits and vegetables are consumed pureed.
Slow chewing is critical; each bite should be chewed 20–30 times, and meals should last 20–30 minutes. Every meal starts with protein. When satiety is felt, the meal ends immediately — "one more bite" habits create risk for the healing staple line.
By the end of the second month, gradual transition to solid foods begins. Eggs, chicken breast, fish, turkey, and legumes are primary protein sources. Daily protein target remains 60–80 g. Refined carbohydrates, sugary foods, and high-fat processed items are avoided.
Eating pattern is structured as three main meals and two snacks. Total calories begin at approximately 800–1,000 kcal and gradually rise to 1,200–1,500 kcal based on metabolic needs. High-sugar foods can trigger dumping syndrome and should be avoided.
Certain vitamin and mineral supplements are required for life after sleeve gastrectomy [1][2]. A daily multivitamin is recommended for all patients. Vitamin B12 is taken as 500 μg orally per day or as monthly injections.
Vitamin D3 is recommended at 1,000–2,000 IU daily, and calcium citrate at 1,200–1,500 mg daily. Iron deficiency is common, particularly in menstruating women, and supplementation is added as needed. Annual blood testing — complete blood count, ferritin, B12, vitamin D, calcium, and parathyroid hormone — identifies deficiencies early. All dosing and follow-up should be individualized under medical supervision.
Bariatric surgery does not produce identical results for every patient; BMI, coexisting conditions, age, and individual medical history all shape outcomes. Whether sleeve gastrectomy is appropriate for you can only be determined through a comprehensive clinical evaluation. For information about your medical condition and current health status, you may contact the clinic through the provided channels. A detailed assessment of your health is the most accurate step in choosing the right method.
Disclaimer: Results of any surgical or interventional procedure may vary from person to person. It is recommended that you obtain detailed consultation from your physician before any procedure.
[1] IFSO Global Registry Report 2023 — https://www.ifso.com/ifso-registry/
[2] 2022 ASMBS and IFSO Indications for Metabolic and Bariatric Surgery — https://asmbs.org/resources/metabolic-and-bariatric-surgery
[3] Laparoscopic Sleeve Gastrectomy — Long-term Outcomes, Systematic Review (PubMed) — https://pubmed.ncbi.nlm.nih.gov/
[4] Turkish Society of Bariatric and Metabolic Surgery — https://www.tbmcd.org.tr/
[5] WHO Obesity and Overweight Fact Sheet — https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
The most common questions about this treatment
No, sleeve gastrectomy is not reversible; approximately 80% of the stomach is permanently removed and cannot be restored. However, if needed, revision surgery can convert a sleeve to gastric bypass or duodenal switch. This permanence underscores the importance of careful candidate selection and thorough preoperative evaluation.
According to the literature, the average patient loses approximately 60–70% of excess weight in the first year. The peak of 65–75% EWL is reached during the second year. For example, a patient with 40 kg of excess weight may lose 24–28 kg in the first year. Results vary based on age, starting BMI, sex, nutritional adherence, and physical activity.
Laparoscopic sleeve gastrectomy takes 60–90 minutes in experienced hands. General anesthesia is safely administered to patients with obesity using standard preoperative evaluation and modern anesthesia protocols. Mortality rates in accredited centers are reported at 0.1–0.3% in the literature. The anesthesia team's experience with patients with obesity is an important safety factor.
Preparation typically takes 4–6 weeks. After the initial consultation, endoscopy, blood work, psychological evaluation, and anesthesia consultation are completed. During the final 2–4 weeks, a protein-focused liquid or low-carbohydrate diet reduces liver volume and improves surgical safety. Unless clinically urgent, this process should not be rushed.
This decision depends on BMI, comorbidities, reflux history, and lifestyle. In severe GERD or poorly controlled type 2 diabetes, gastric bypass may be preferred. Super-obese patients (BMI > 50) with multiple comorbidities may also benefit from bypass. Moderately obese, younger patients without reflux may be candidates for sleeve gastrectomy. The final decision is made through comprehensive clinical evaluation.
Pregnancy, breastfeeding, untreated severe psychiatric illness, active eating disorders, active substance dependence, and untreated endocrine obesity (Cushing's syndrome, severe hypothyroidism) are absolute or relative contraindications. Patients with severe GERD and large hiatal hernia may be considered for alternative procedures. Each patient's situation is assessed individually.
After year five, approximately 15–20% of patients experience meaningful weight regain. Protective factors include regular exercise, protein-focused nutrition, continuous multidisciplinary follow-up, and not skipping meals. Psychological support helps sustain behavioral changes. When regain is identified early, behavioral interventions are usually sufficient.
Desk-based workers typically return in 2–3 weeks. Physically demanding work may require 4–6 weeks. The first week is home recovery, with light walking starting in week two. Heavy lifting and intense exercise are restricted for 6–8 weeks. Full recovery and return to normal activities take approximately 3 months.
Not restricted — mindful. Portions become permanently smaller, protein-first eating becomes habitual, and processed foods are avoided. The first six months are a disciplined transition; after that, social meals, celebrations, and diverse cuisines return to your life. The goal is not a "diet" but a sustainable lifestyle.
Sleeve gastrectomy often improves fertility, and marked improvement is seen in polycystic ovary syndrome. However, pregnancy is not recommended during the rapid weight-loss phase. Waiting at least 12–18 months after surgery and using effective contraception during this period is advised. Once weight stabilizes and vitamin levels are within normal range, pregnancy can be planned.
Because sleeve gastrectomy is performed laparoscopically, incisions measure only 0.5–1 cm. Aesthetic suturing techniques minimize scarring, and scars fade significantly over time. Scar care creams may be recommended after wound healing. Compared with open surgery, visible scarring is minimal.
Significant weight loss can lead to loose skin in the abdomen, arms, thighs, and breasts. The extent depends on age, skin elasticity, amount of weight lost, and genetics. Resistance training, adequate protein intake, and skin care reduce loosening. In pronounced cases, body contouring surgery may be considered 12–18 months after weight stabilization.
Explore other bariatric surgery options
Gastric bypass (Roux-en-Y) is an established bariatric procedure in which a small pouch of approximately 30 mL is created from the stomach and a section of the small intestine is bypassed. It both restricts food intake and alters the absorption pathway. It is often a preferred option for patients with type 2 diabetes alongside obesity.
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Mini gastric bypass (one anastomosis gastric bypass, OAGB) is a laparoscopic bariatric procedure in which the stomach is reshaped into a long tubular pouch along the lesser curvature, connected to the small intestine with a single anastomosis. It combines restrictive and malabsorptive features and is generally performed in a shorter operative time than Roux-en-Y bypass.
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The gastric balloon (intragastric balloon) is a temporary, non-surgical treatment option for obesity, placed endoscopically inside the stomach and generally removed after approximately six months. It is considered in patients with BMI 27-40 who are not surgical candidates.
Learn MoreFor detailed information about bariatric and metabolic surgery procedures, you may use the contact channels below. Initial consultations for international patients can be arranged remotely via video call or WhatsApp.
Assoc. Prof. Dr. Hasan Abuoğlu
Associate Professor of General Surgery
