VSG, or vertical sleeve gastrectomy, is a weight loss surgery that permanently removes roughly 75 to 80% of the stomach, leaving behind a narrow, tube-shaped pouch about the size of a banana. It is the most commonly performed bariatric surgery worldwide, and it works through two mechanisms: physically limiting how much food you can eat and changing the hormonal signals that drive hunger. Most patients lose about 45% of their excess weight in the first year, with results peaking around 72 to 76% of excess weight lost by year three.
How the Procedure Works
The surgery is performed laparoscopically, meaning a surgeon uses several small incisions and a camera rather than one large opening. During the operation, the surgeon removes the large, curved portion of the stomach called the fundus along with most of the stomach body. What remains is a narrow sleeve that runs from the esophagus down to the first part of the small intestine. The intestines themselves are not rerouted or bypassed, which makes VSG simpler than gastric bypass and reduces some surgical risks.
The operation typically takes 60 to 90 minutes. Most patients stay in the hospital for one to two nights before going home.
Why It Reduces Hunger, Not Just Stomach Size
The fundus, the portion of stomach that gets removed, happens to be the main production site for ghrelin, the hormone that signals hunger to your brain. After a sleeve gastrectomy, plasma ghrelin levels drop significantly because those ghrelin-producing cells are physically gone. This is a key reason patients report feeling dramatically less hungry after VSG, not just full sooner. The combination of a smaller stomach, reduced hunger hormones, and changes in other gut hormones that regulate blood sugar and satiety accounts for the sustained weight loss that simple dieting rarely achieves.
Who Qualifies for VSG
The joint 2022 guidelines from the American Society of Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity recommend surgery for anyone with a BMI above 35, regardless of whether they have other health conditions. For people with a BMI between 30 and 34.9, surgery should be considered if they also have a metabolic condition like type 2 diabetes, high blood pressure, or sleep apnea.
BMI thresholds are lower for people of Asian descent: a BMI above 27.5 qualifies for surgery, reflecting the higher metabolic risk that occurs at lower body weights in this population. Adolescents with severe obesity are also eligible under separate pediatric guidelines.
Most insurance plans and surgical programs require documentation of previous weight loss attempts, a psychological evaluation, and sometimes a period of medically supervised dieting before approving the procedure.
Expected Weight Loss Timeline
Weight loss is fastest in the first six months and continues at a slower pace through years two and three. In a large cohort study, patients averaged about 45% of excess weight lost at one year and roughly 66% at two years, with peak results around three years. “Excess weight” means the weight above what’s considered a healthy BMI, so someone who carries 100 pounds of excess weight might expect to lose 45 to 70 of those pounds.
Results vary. Some patients exceed these averages, while others fall short, particularly if eating habits don’t change long-term. Weight regain of 10 to 15% from the lowest point is common after the three-year mark, which is why surgical teams emphasize ongoing dietary and behavioral support.
Impact on Diabetes and Other Conditions
VSG can push type 2 diabetes into remission, not just improve it. A Swedish registry study tracking thousands of patients found that 58% achieved complete diabetes remission within two years, meaning their blood sugar levels returned to normal without medication. At five years, 47% still maintained complete remission. An even larger group, about 77%, were off diabetes medications entirely at the two-year mark even if their blood sugar wasn’t quite in the “normal” range.
The duration of diabetes before surgery matters. People who have had diabetes for a shorter period respond better, while those who have been managing it for a decade or more are less likely to achieve full remission. Improvements in sleep apnea, joint pain, and cholesterol levels are also well-documented after VSG, though specific remission rates vary.
Risks and Complications
VSG is considered a safe procedure. The 30-day mortality rate sits at roughly 0.04 to 0.11%, making it comparable in risk to a gallbladder removal. Overall complication rates across bariatric surgeries fall between 10 and 17%, though most of these are minor issues like nausea or dehydration that resolve quickly.
The most serious early complication is a staple line leak, where the long seam created during surgery doesn’t seal properly. This is uncommon but requires urgent treatment. Bleeding along the staple line is another possibility, occurring in a small percentage of cases.
The complication that gets the most long-term attention is acid reflux. Studies show that new-onset reflux develops in a significant number of VSG patients. One study found that over half of patients reported new reflux symptoms at 12 months, though this dropped to about 30% by the three-year mark. For people who already have severe reflux before surgery, gastric bypass is often recommended instead because it tends to improve reflux rather than worsen it.
Recovery and the Post-Surgery Diet
The dietary progression after VSG follows a strict, phased approach that gradually reintroduces texture over about eight weeks.
- Days 1 to 2: Clear liquids only, including water, broth, and sugar-free gelatin.
- Days 3 to 7: Full liquids like skim milk, protein shakes, and decaffeinated coffee or tea.
- Weeks 2 to 4: Pureed foods with the consistency of a smooth paste. Meals are tiny, about 4 to 6 tablespoons each, eaten three to six times a day.
- Weeks 4 to 8: Soft foods cut into small, easily chewed pieces. Portions grow slightly to about one-third to one-half cup per meal.
- After week 8: Gradual return to solid foods, with meals of roughly 1 to 1.5 cups.
Most people return to work within two to four weeks, depending on how physically demanding their job is. Strenuous exercise is typically cleared around six weeks post-surgery.
Lifelong Vitamin Requirements
Because the stomach is permanently smaller and absorbs certain nutrients less efficiently, you will need to take supplements for the rest of your life after VSG. This is not optional. Deficiencies can develop silently over months or years and cause serious problems like anemia, bone loss, and nerve damage if left unchecked.
The core supplements include a daily multivitamin with minerals, vitamin B12 (350 to 500 micrograms daily by mouth, or a monthly injection), calcium citrate (1,200 to 1,500 milligrams daily from all sources, split into two or three doses for better absorption), and iron. Menstruating women and anyone with a history of anemia need 45 to 60 milligrams of elemental iron daily. Men and others at lower risk need at least 18 milligrams, which a good bariatric multivitamin typically covers.
Your surgical team will monitor bloodwork at regular intervals, usually every three to six months in the first year and annually after that, to catch any deficiencies early.