What is a mini gastric bypass?
A mini gastric bypass, also called a one anastomosis gastric bypass (OAGB), is a weight loss operation that works in two ways. First, the surgeon turns the upper stomach into a long, narrow pouch, so you feel full after small amounts of food. Second, this pouch is joined directly to a loop of small intestine further down, so food skips roughly 200–250 cm of bowel. Fewer calories are absorbed, and changes in gut hormones help to reduce appetite.
The name comes from the standard Roux-en-Y gastric bypass. The mini version needs only one join (anastomosis) instead of two, which makes it a shorter and technically simpler operation. It shares features of both the gastric sleeve and the standard bypass. The rest of the stomach stays inside your body but no longer carries food.
Who is it suitable for?
A mini gastric bypass is used to treat obesity and the health problems linked to it, such as type 2 diabetes, high blood pressure, high cholesterol and sleep apnoea. It is also a common revision operation for patients whose gastric band or sleeve has not worked. The bariatric team generally considers patients who:
have a BMI of 35 or more, or a BMI of 30 or more with a weight-related condition
have not achieved lasting weight loss with diet and exercise
do not have severe acid reflux or reflux caused by a hiatus hernia
have no active infection and no recent COVID-19 infection in the month before surgery
are willing to stop smoking and drinking alcohol well before surgery
If you have a chronic condition such as diabetes or high blood pressure, you may be asked for extra test results before you travel.
Preparing for surgery
Once you are accepted, your coordinator sends a liver-reducing diet to follow for the weeks before you fly. It shrinks the liver and makes keyhole surgery safer. You will also be asked to:
stop hormonal contraception and HRT around 30 days before surgery, because they raise the risk of blood clots
stop vitamin K supplements around 30 days before surgery
avoid smoking from at least a week before until three weeks after the operation, as it slows healing
avoid alcohol in the months before surgery
fast for around 12 hours before the operation
How the operation is done
The operation is performed by keyhole surgery under general anaesthesia and usually takes 60 to 90 minutes.
Tests and consultations
On arrival you have blood tests, an abdominal ultrasound, a chest X-ray, an ECG, a breathing test and an endoscopy. You meet the surgeon, the anaesthetist, an internal medicine specialist and a radiologist, who confirm you are fit for surgery.
Keyhole access
The surgeon makes 4 to 6 small incisions in the abdomen and passes a camera and fine instruments through them.
Creating the pouch
A stapler divides the stomach to form a long, narrow pouch. The larger remaining part of the stomach is left in place but no longer receives food.
Joining the intestine
The surgeon measures out a length of small intestine and joins a loop of it to the end of the pouch. The join is checked for leaks before the incisions are closed with dissolving stitches.
Recovery timeline
- First 24 hours
You are helped out of bed within a few hours to get your circulation moving. You receive pain relief, blood-thinning injections and medication to protect the stomach.
- Days 2–5
You start sipping clear fluids once the team is happy with the join. After 4 nights in hospital you are discharged to the hotel for your final day.
- Weeks 1–3
You stay on liquids such as protein shakes, clear soups and herbal teas. Walk every day. Most people can return to desk work about two weeks after getting home.
- Weeks 4–6
Puréed and mashed foods are added. Avoid lifting anything over 5 kg during the first month and anything over 10 kg for three months.
- Months 2–24
You return to solid food in small portions and can begin regular exercise from about two months. Weight loss is fastest in the first year.
Eating after a mini gastric bypass
never eat and drink at the same time; leave a gap of about 30 minutes
eat slowly, chew well and stop when you feel full
put protein first at every meal
avoid fizzy and caffeinated drinks for at least three months; decaffeinated coffee is usually fine after about 10 days
limit sugary and fatty foods, which can trigger dumping syndrome
take your bariatric vitamins and minerals every day, for life
Risks and side effects
Every major operation carries risks, and your surgeon will explain them before you consent. In the first weeks they include:
leakage from the join or staple line
bleeding
infection
blood clots in the legs or lungs
bowel obstruction
reactions to the anaesthetic
Longer-term problems can include acid or bile reflux, ulcers near the join, incisional hernia, gallstones during rapid weight loss, dumping syndrome and vitamin or mineral deficiencies. Endoscopy of the bypassed stomach is also more difficult later on. Blood thinners, compression stockings, daily supplements and regular blood tests lower many of these risks. If severe reflux develops, the operation can be converted to a standard Roux-en-Y bypass.
Results
Most patients lose a large proportion of their excess weight over 12 to 24 months, and conditions such as type 2 diabetes, high blood pressure and sleep apnoea often improve or resolve. Less weight also eases pressure on the knees and hips. Results last best when you keep to the eating habits you learn after surgery. Returning to overeating or regular fizzy drinks can lead to weight regain.
Mini gastric bypass in Turkey: your trip
Before you fly
You send your height, weight, medical history and any recent test results. The team reviews them with the surgeon and sends you a treatment plan and your pre-operative diet. Once you accept, we confirm your surgery date.
In Istanbul
A VIP driver meets you at the airport. A translator stays with you through tests, consultations and discharge, and a companion can stay with you at no extra cost. Your hospital stay, tests, surgery, medication and meals are covered by the package.
Back home
Your coordinator is available 24/7 on WhatsApp, follows your diet stages and passes any questions to the surgical team. Dissolving stitches usually disappear on their own; if not, your GP can remove them.
What the Mini Gastric Bypass package includes
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Hospital and medical care
Your private hospital room, nursing care, pre-operative tests, consultations with your surgeon, anaesthesia, the operation itself and the medication you take home.
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VIP transfers
A private driver meets you at the airport and takes you between the airport, your hotel and the hospital.
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Translator and companion
A medical translator at the hospital, and a companion can travel with you at no extra cost.
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Meals and comfort
Daily meals for you and your companion throughout your stay.
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24/7 patient coordinator
A dedicated coordinator answers your questions before, during and after your trip, in your language.
Your surgeons for Mini Gastric Bypass
Mini Gastric Bypass FAQ
How is a mini gastric bypass different from a standard gastric bypass?
A standard (Roux-en-Y) bypass needs two joins in the bowel, while the mini bypass needs only one. That usually makes the operation shorter. The trade-off is a higher chance of bile reflux, which your surgeon will discuss with you.
How much weight can I expect to lose?
Most patients lose a large share of their excess weight, typically around 70–80%, over the first one to two years. Your own result depends on your starting weight, how well you follow the diet plan and how active you stay. Your surgeon will give you a realistic estimate at your consultation.
Am I eligible?
The bariatric team usually considers a BMI of 35 or more, or 30 or more with a weight-related condition such as type 2 diabetes or high blood pressure. Severe acid reflux or reflux caused by a hiatus hernia may make another operation a better choice. The final decision is made after your tests in Istanbul.
Can a mini gastric bypass be reversed?
Unlike a sleeve, no part of the stomach is removed, so the operation can in principle be reversed or converted to a standard bypass. Reversal is still a major operation and is only done for a clear medical reason.
Is it a good option if my gastric sleeve or band did not work?
Yes, it is often used as a revision operation after a sleeve or band that has not given lasting results. Revision surgery is more complex, so the team reviews your previous operation notes and test results before recommending it.
How long will I be on liquids?
Usually about three weeks of liquids, then around three weeks of puréed food, before soft and then normal textures are introduced. A dietitian's plan is provided and your coordinator follows your progress on WhatsApp.
Will I need vitamins for life?
Yes. Because part of the intestine is bypassed, your body absorbs less iron, calcium, vitamin B12 and other nutrients. You will need bariatric supplements every day and regular blood tests with your GP.
When can I fly home?
Plan for 5 days in Istanbul, including 4 nights in hospital. Most patients fly home on day 5, once the surgeon has checked them. Wear compression stockings, drink water and walk the aisle regularly during the flight.
