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One Anastomosis Gastric Bypass

One Anastomosis Gastric Bypass (OAGB) is also known as Single Anastomosis Gastric Bypass, Mini Gastric Bypass or Omega Loop Gastric Bypass.
It utilises laparoscopic techniques or “keyhole” surgery to provide a minimally invasive procedure. OAGB reduces the gastric capacity and allows a person to feel comfortably satisfied and full with a meal size approximately equivalent to ½ to 1 cup of food. It is thus a partially restrictive bariatric operation. 
It is also a partially malabsorptive bariatric procedure that bypasses approximately 1.5 metres of small bowel.


The major reduction in stomach capacity allows patients to become satisfied with a much smaller meal, providing portion control. There is also an aspect of malabsorption (where you do not absorb all the nutrients that you consume) allowing patients to lose weight quickly initially. OAGB also allows for the possibility of revision or reversal if needed, as nothing is actually removed from the body. Nil need for adjustments like the Gastric Band.


Lifelong supplements and regular blood tests due to the malabsorption aspect of this surgery in order to avoid deficiencies. Bowel habits will be noticeably different and will react more quickly to foods, requiring adherence to foods that do not cause negative effects and avoiding the foods that do.

As with any weight loss surgery procedure, lifestyle changes need to be made in order to maintain long term weight loss. It is important to understand that any weight loss surgery requires a life-long partnership between the patient and the surgical team, requiring long term follow up care to ensure the best possible results are achieved.