Sleeve surgery, formally called vertical sleeve gastrectomy, is a weight loss procedure where a surgeon permanently removes roughly 75 to 80 percent of your stomach. What remains is a narrow, banana-shaped tube about the size of a banana. This smaller stomach holds significantly less food, but it also changes your body’s hunger signals in ways that make the surgery more effective than simple portion control.
How the Surgery Works
The procedure is performed laparoscopically, meaning the surgeon works through several small incisions rather than one large opening. Using surgical staples, the surgeon divides the stomach vertically and removes the larger, curved portion. The remaining sleeve is sealed along the staple line, creating a tube that connects your esophagus to your small intestine just as before. No rerouting of the intestines is involved, which is one reason the sleeve is considered simpler than gastric bypass.
The operation typically takes one to two hours. Most people stay in the hospital overnight and go home the next day.
Why It Reduces Hunger, Not Just Stomach Size
The removed portion of the stomach happens to be where your body produces most of its ghrelin, the hormone responsible for stimulating hunger. After sleeve surgery, ghrelin levels drop substantially. This means you’re not just physically limited in how much you can eat. You genuinely feel less hungry throughout the day, which makes it easier to stick with smaller meals long term. This hormonal shift is one of the things that sets the sleeve apart from older approaches like gastric banding, which only restricted stomach size without changing appetite chemistry.
Who Qualifies
Updated guidelines from the American Society for Metabolic and Bariatric Surgery recommend the procedure for anyone with a BMI above 35, regardless of whether they have other health conditions. For people with a BMI between 30 and 35 who also have metabolic conditions like type 2 diabetes, surgery can still be appropriate. These thresholds were expanded in 2022 to reflect growing evidence that people at lower BMIs can benefit significantly, particularly when weight-related diseases are already present.
Most insurance plans and surgical programs also require that you’ve attempted other weight loss methods without lasting success, though the specific requirements vary.
Expected Weight Loss
In the first year after surgery, most people lose 60 to 70 percent of their excess weight. “Excess weight” means the weight above what’s considered a healthy BMI for your height, so someone carrying 100 extra pounds could expect to lose roughly 60 to 70 of those pounds within 12 months. Most patients reach their lowest weight somewhere between 12 and 24 months after the operation.
Long-term data from multiple centers shows that the majority of patients maintain their weight loss at the five-year mark. That said, some weight regain is common after the initial low point, and ongoing dietary habits and physical activity play a major role in sustaining results.
Risks and Complications
The most significant surgical complication is a staple line leak, where the sealed edge of the new stomach doesn’t heal properly and stomach contents seep into the abdominal cavity. This occurs in roughly 1 to 3 percent of patients on average, though rates as high as 5.5 percent have been reported in some studies. A leak can be serious, sometimes requiring additional procedures and extended hospital stays, but it remains relatively uncommon.
Acid reflux is another concern. Some people develop new reflux symptoms after sleeve surgery, or find that existing reflux gets worse. The smaller, tube-shaped stomach can increase pressure at the junction with the esophagus. For people who already have significant reflux before surgery, a gastric bypass may be recommended instead, since that procedure tends to improve reflux rather than worsen it.
Other possible complications include blood clots, infection at the incision sites, and narrowing of the sleeve (called a stricture), though these are less common.
Recovery and the Post-Surgery Diet
Recovery from the surgery itself is relatively quick. Most people return to non-strenuous work within one to two weeks. The bigger adjustment is dietary. Your stomach needs time to heal along the staple line, so you’ll follow a structured diet progression over six weeks before eating regular food again.
The four stages look like this:
- Weeks 1 and 2: Smooth liquids only, like broth, protein shakes, and water.
- Weeks 3 and 4: Pureed foods with the consistency of baby food.
- Weeks 5 and 6: Soft foods like scrambled eggs, cooked vegetables, and tender fish.
- Week 7 onward: Gradual return to regular-textured foods.
Meals stay small permanently. Your new stomach holds only a few ounces at a time, so eating slowly and chewing thoroughly becomes essential. Most people settle into a pattern of three small meals plus one or two protein-rich snacks per day.
Lifelong Vitamin and Mineral Supplements
Because your stomach is so much smaller, you absorb fewer nutrients from food. Supplementation isn’t optional after sleeve surgery. It’s a permanent part of your routine. The key supplements include:
- Multivitamin with minerals: A daily multivitamin forms the base, covering zinc, copper, vitamin E, and vitamin K.
- Calcium: 1,200 to 1,500 milligrams per day, taken in divided doses for better absorption. Calcium citrate is preferred because it absorbs without needing stomach acid.
- Vitamin D: 3,000 IU daily until blood levels reach a sufficient range, then adjusted as needed.
- Vitamin B12: 350 to 500 micrograms daily by mouth (sublingual or dissolvable tablet), or a monthly injection.
- Iron: At least 45 to 60 milligrams of elemental iron daily, particularly important for menstruating women. Iron should be taken separately from calcium for proper absorption.
- Vitamin B1 (thiamin): At least 12 milligrams daily, ideally 50 milligrams through a B-complex supplement.
- Folate: 400 to 800 micrograms daily, with higher doses for women of childbearing age.
Skipping these supplements puts you at risk for deficiencies that can cause fatigue, hair loss, bone thinning, and neurological problems. Regular blood work, usually every three to six months in the first year and annually after that, helps catch any gaps early.
How It Compares to Other Weight Loss Surgeries
The sleeve gastrectomy is currently the most commonly performed bariatric surgery worldwide. Compared to gastric bypass, it’s a simpler operation with a shorter surgical time and no intestinal rerouting, which means a lower risk of certain complications like bowel obstruction and nutrient malabsorption. However, gastric bypass tends to produce slightly more weight loss overall and is better for people with severe reflux.
Compared to the adjustable gastric band (lap band), the sleeve produces significantly more weight loss and doesn’t require a foreign device left inside the body. The trade-off is that the sleeve is irreversible. Once the stomach tissue is removed, it cannot be restored. For most patients, the stronger and more durable results make the sleeve the preferred option.