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Do I need surgery?

There are a number of widely accepted criteria which make a patient suitable for Bariatric or weight loss surgery:

  • Weight greater than 45kg above the ideal body weight for sex, and height 

  • BMI > 40 by itself or >35 if there are associated comorbidities E.g. obesity illness, such as diabetes or sleep apnoea 

  • Reasonable attempts at other weight loss techniques

  • Age 18-65 

  • Obesity related health problems 

Do I need surgery?

Weight Loss Surgery

Body Mass Index (BMI) Calculator

BMI is a calculation of the balance between your height and your weight. It is a general approach used in determining the amount of body fat you carry and is the first measuring tool when considering levels of obesity.

Do I qualify for surgery?

Do I qualify for surgery?

There is considerable flexibility in these guidelines. Patients as young as 12 have been offered surgery. Sometimes a lower BMI between 30-35 is accepted if potentially severe and life threatening comorbidities exist.

  • Is my BMI > 40, or > 35 with co-morbidities (see our BMI calculator to calculate your BMI) 


  • Co-morbidities are other medical conditions such as type two diabetes or sleep apnoea or arthritis 


  • There may be times when a lower BMI (<35kg/m²) may be considered, however this will be at the discretion of the team and must be discussed with the team (please advise us on phoning your BMI is on the lower side)  ​

As well as the medical reasons, there are also some other factors we need to consider before approving a patient for surgery. Largely they are more behavioural elements, and some of the questions you need to ask yourself are:

​Questions to ask yourself:​

  • Have you dieted in the past?

  • Do you think you may need help?

  • Can you commit to surgery as a tool and use behaviours to determine your long term success?

Our Surgical Weight Solutions

Our Procedures
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Fobi Pouch Roux-en-Y Gastric Bypass

A gastric bypass can aid weight loss by restricting the amount of food the stomach can hold. It also alters the way food gets passed through the digestive system, thereby resulting in fewer calories to be absorbed.​​​


This procedure is performed in a minimally invasive manner with the help of small incisions, smaller surgical instruments, and a laparoscope.​

We offer the addition of a fobi pouch (silastic ring) as less weight regain is observed


Gastric Sleeve

The Gastric Sleeve is a restrictive procedure meaning that it achieves weight loss results by restricting the amount of food that your body is physically able to take in. There is no malabsorption involved with this procedure. Gastric Sleeve surgery involves permanently removing a large portion of the stomach, anywhere from 60% to 85% of the total stomach.

The portion left behind is a slim tube or “sleeve” that will serve as your new stomach. This stomach is already connected naturally to the stomach inlet and outlet which means that no rerouting of the intestines is needed. 

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Mini Gastric Bypass

Mini gastric bypass or sometimes called 'loop gastric bypass', 'omega loop gastric bypass' or 'one anastomosis' gastric bypass.


Gastric Band

This operation is no longer performed. However, we do offer gastric band revisional surgery for patients.

SADI-S Information

Laparoscopic Single Anastomosis Duodenal-Ileal bypass with Sleeve, also known as SADI-S, is relatively new bariatric technique to achieve weight loss. It is a good option for patients with severe obesity, for both the primary setting and as a revisional procedure after failure of a sleeve gastrectomy. Patients can achieve 85-95% excess weight loss at 5 years. 


SADI-S is a laparoscopic procedure and consists of two steps. The first is forming a “sleeve gastrectomy”, where almost 80% of the stomach is removed to form a narrow tube. Next, a small bowel bypass is performed to reduce the surface for food absorption. These anatomical changes decrease oral intake and reduce the absorption of the nutrients and calories eaten.

Biliopancreatic Diversion with Duodenal Switch information

Biliopancreatic diversion with Duodenal Switch (DS) is a highly effective weight loss surgical operation. During this procedure, a sleeve gastrectomy is formed, and the first part of the small bowel (duodenum) is then connected to the last 250cm of small bowel, bypassing about two-thirds of the total length of small bowel. After this operation, the amount of food you can eat is reduced and the absorption of fat, proteins and calories is reduced.

Excess weight loss is typically around 80-100% with a low risk of long-term weight regain. DS also offers excellent chances of improvement or resolution of obesity-related diseases such as type 2 diabetes, hypertension, dyslipidaemia, fatty liver disease and Obstructive Sleep Apnoea.

The risk of long term metabolic complications following DS is higher compared to other bariatric procedures. Due to the significant reduction in absorption of nutrients there is a higher long-term risk of vitamin and protein deficiencies. For this reason, this procedure requires close medical monitoring with regular blood tests, strict adherence to dietary recommendations and vitamin and mineral supplementation. 

Revisional Surgery

If you have had complications with previous surgery we are also able to provide solutions which can help.

Weight Loss Surgery: Service

Weight loss after surgery

Approximately 60-70% of excess weight can be lost if the general rules pertaining to exercise and diet are followed post-operatively. Some weight regain is commonly seen at 18 months but sustained weight loss in the order of 50% of excess weight loss is generally seen at 5 years and beyond.

Most weight loss is seen in the first 12 months. Sometimes it can be precipitous which is not of concern as long as vitamins and adequate protein, 60-80g, per day are taken.

Sometimes patients plateau for periods and do not lose weight. This may last from a few weeks to longer but weight loss resumes as long as the correct diet and exercise recommendations are being followed.

If sudden weight gain occurs then xrays may need to be taken to see if the staple lines have disrupted. This is generally seen at a later date and the incidence has reduced now that the stomach is divided between staple lines.

Swedish Obesity Study: Weight Loss with Surgery versus Control Group


Swedish Obesity Study: Mortality with Surgery versus Control Group


These graphs from the large Swedish Obesity Study shows bariatric surgery versus conventional obesity treatment (matched control group) was associated with long-term weight loss and a decreased risk of death.  


Sjöström, L. et al (2007). Effects of Bariatric Surgery on Mortality in Swedish Obesity Subjects. The New England Journal of Medicine; 357: 741 – 752. 

Carlsson, L. et al (2020). Life expectancy after Bariatric Surgery in the Swedish Obesity Subjects Study. New England Journal of Medicine; 383: 1535 – 1543.

Percentage Excess Weight Loss after Loop Gastric Bypass at 11 years


This study shows the loop gastric bypass appears to be a safe and effective operation promoting good weight loss extending out to 11 years post-surgery.


Sheikh, L., Pearless, L. & Booth, M. (2017). Laparoscopic Silastic Ring Mini-Gastric Bypass (LR MGB): Up to 11-Year Results from a Single Centre. Obesity Surgery; 27(9): 2229-2234.

Weight Loss After Surgery
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