Patient BlogWeight Loss Surgery

One-Anastomosis Gastric Bypass, also known as Mini Gastric Bypass, or Omega Loop Gastric Bypass is a bariatric procedure. Bariatric procedures are designed to help obese or severly obese individuals lose excess weight by modifying parts of their digestive tract.

There are several weight-loss procedures available, including sleeve gastrectomy, endoscopic sleeve gastroplasty, gastric balloon, and SASI-S, among the others. Patients who are planning a bariatric procedure often suffer from diseases that are related to their weight. These procedures can help them immensely to become healthier and improve their quality of life. Each patient will be assessed on an individual case to establish which procedure is the right one for them.

One-Anastomosis Gastric Bypass, or OAGB surgery, was developed at the end of the 1990s and has gained much popularity especially in the last few years thanks to its safety and reliable results. In this article, we are going to examine this procedure, how it works, who it is for, and what you should expect after the operation.

Want to know more about the Gastric Bypass?
Contact us and we will clear your doubts

How does One-Anastomosis Gastric Bypass (OAGB) work?

One-Anastomosis gastric bypass is performed under general anaesthesia. This means that you will be asleep throughout the procedure. OAGB surgery is performed using a laparoscope, so incisions will be minimal. The surgeon will create five small incisions in your abdomen that will be the access points for special surgical instruments.

OAGB surgery involves two steps. First, the surgeon will divide the stomach in two unequal parts using surgical staples. Only the smaller part of the stomach (around 25% of its original size) will be used going forward. The larger portion will remain unutilised and won’t be involved in the digestive process any longer.

Secondly, the surgeon reroutes a large portion of the small intestine (duodenum) and part of the bowel by connecting it to the smaller portion of the stomach. This bypass does not require as much surgical rerouting as in the traditional gastric bypass. That’s why this procedure is also known as mini gastric bypass.

OAGB surgery works on one hand as a restrictive procedure because, as the stomach is made smaller, the patient is unable to eat as much as they did before surgery and will feel full sooner and longer. Moreover, OAGB surgery also works through malabsorptive techniques: since the small intestine has been rerouted, the food being digested does not stay in the digestive tract as long. This way, the body doesn’t have the time to extract and absorb all the calories and nutrients.

With lower quantities of food ingested and reduced absorption, patients typically will lose a significant amount of weight in a relatively short time.

Who is One-Anastomosis Gastric Bypass (OAGB) for?

OAGB surgery, as all bariatric surgeries, will be recommended on a case-to-case basis. However, these are the general guidelines to be eligible:

  • Individuals whose BMI is 40 or greater. You can calculate your Body Mass Index here;
  • Individuals whose BMI is 35 and have one or more obesity-related diseases such as type 2 diabetes or high blood pressure.

What should I expect after a One-Anastomosis Gastric Bypass (OAGB)?

After the procedure, you will need to stay at our clinic for 2-3 days. During this time, our nurses and medical staff will take care of you. You will receive an extensive post-op programme for you to follow once you’re back home, which entails diet and work-out recommendations. Like for all bariatric surgeries, post-op guidelines are crucial to ensure that your procedure is successful. Make sure that you follow your doctor’s recommendations carefully and be ready to embrace a rather different lifestyle. This will help you in the long run!

Bariatric procedures can be seen as a ‘tool’ to help patients lose weight. Similarly to other weight-loss procedures, OAGB surgery typically causes a 75% loss of excess body weight over two years. This is possible only with the full commitment of patients to drastically changing their eating habits and lifestyle. These typically include eating in small portions, having a regular exercise plan, and avoiding fried foods, sweets, and sodas.

OAGB surgery is considered a reversible procedure, so the mini gastric bypass can be reversed after some time if deemed necessary.

How do I get started?

First of all, feel free to get in touch with us at KCM Clinic using this form. One of our patient coordinators will be in touch and will discuss with you: your medical history, current diseases or illnesses you may have, as well as any medications you’re taking. They will walk you through the procedure and answer any questions you might have.

After our medical staff has confirmed that you are eligible for the procedure, you will arrange a treatment date with our coordinators. We offer convenient packages for international patients, and we’ll gladly pick you up from the airport or train station, if necessary. Before your arrival, you will be given a pre-op diet plan that you should follow in order to prepare for the operation. It is very important that you follow these guidelines carefully!

To find out more about how we make it easy to travel for our patients, feel free to read this article.

The experts at KCM Clinic are here to help you navigate through your weight-loss journey. Contact us anytime – from determining what procedure is right for you to keeping tabs on your recovery once you’re back home, we’ll offer our continuous support and guidance towards a healthier you.

Gastric Bypass
Find out more about laparoscopic gastric bypass
Gastric Bypass

Send Request

    By completing the form, I agree with Privacy policy and the method of using the sent data.

    I consent to the processing of my personal data by KCM Clinic S.A. based in Jelenia Góra in order to send marketing content to my e-mail address provided above in the contact form.


    Visits, hospital procedures

    Bariatric Surgery Center

    Plastic Surgery Center

    Spine Surgery Center

    Dental Clinic

    OMEGA Imaging Diagnostic Center

    Work hours

    • Mon - Fri 7:30 - 21:00
    • Saturday 7:30 - 18:00

    KCM Clinic Wrocław

    • Open by appointment

    Chat KCM Clinic

    • Mon - Fri 8:00 - 19:00


    KCM Clinic Jelenia Góra

    • ul. Bankowa 5-7 58-500 Jelenia Góra

    KCM Clinic Wrocław

    • ul. Krucza 2A 53-406 Wrocław