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One Anastomosis Gastric Bypass

One Anastomosis Gastric Bypass (OAGB), sometimes called a mini gastric bypass, is a bariatric procedure designed to support significant weight loss while improving many obesity-related medical conditions.
It combines stomach restriction with changes to the digestive tract to help reduce appetite, limit food intake, and improve metabolic health.

About this Procedure What's Involved? Find A Specialist Contact Us

OAGB may be appropriate for patients who:

  • Have obesity affecting their health

  • Have Type 2 diabetes or metabolic syndrome

  • Have previously struggled with sustained weight loss

  • Require a procedure offering strong long-term weight loss outcomes

Your surgeon will discuss whether OAGB or another procedure is the most suitable option for your circumstances.

What's Involved in a One Anastomosis Gastric Bypass?

A One Anastomosis Gastric Bypass (OAGB), sometimes known as a mini gastric bypass, is performed using minimally invasive (keyhole) surgery under a general anaesthetic. During the procedure, the stomach is reshaped into a long, narrow pouch before being connected to a section of the small intestine using a single surgical connection (anastomosis).

This reduces the amount of food the stomach can hold while also altering how nutrients are absorbed. The procedure also affects hormones that regulate appetite and blood sugar, helping patients feel fuller for longer and supporting sustainable weight loss.

What to Expect at Intus

At Intus Dunedin, a One Anastomosis Gastric Bypass is delivered as part of a comprehensive weight management programme rather than as a standalone procedure. From your initial assessment through to your recovery and long-term follow-up, you'll be supported by our multidisciplinary bariatric team.

With access to bariatric nurse specialists, surgeons, nutritionists, psychologists, and dedicated support staff, your care is personalised to help you achieve safe, sustainable, and long-term health outcomes.

Before your procedure

Patients complete a detailed assessment including:

  • Medical review

  • Bariatric nurse consultation

  • Nutritional assessment

  • Psychology support where appropriate

  • Blood tests and investigations

  • Pre-operative diet

After your procedure

Recovery includes:

  • One to two nights in hospital

  • Gradual progression through fluid and soft food stages

  • Ongoing nutritional monitoring

  • Lifelong vitamin supplementation

  • Regular follow-up with the bariatric team

Ready to Explore Your Options?

Contact Us Self Refer to Intus

Our multidisciplinary bariatric team can help you understand whether surgery is the right option for you.

New patients to the Intus Dunedin bariatric service can book a free one-hour consultation with a Bariatric Nurse Specialist to discuss available treatment options, with no obligation to proceed. Contact Intus Dunedin to learn more or book your appointment.

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  • Dr Nigel Rajaretnam

    Upper GI, Bariatric, Endocrine & General Surgeon