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Not all bariatric procedures are equal: what is the right procedure for me?

Updated: May 19, 2023

With the myriad of information available on the internet, it may be difficult for patients to gauge what bariatric procedure will most suit their unique situation. In this guest blog, Dr Thinus Smit gives us tools to answer the question: what is the right bariatric procedure for me? Dr Smit is a bariatric and metabolic surgeon at Zuid-Afrikaans Hospital in Pretoria. He is also the general secretary of the South African Metabolic Medicine and Surgery Society (SAMMSS).

The bariatric surgery umbrella in 2023: what is the right procedure for me?

- Dr Thinus Smit

Because obesity has become one of the biggest diseases of our time, a lot of research is being conducted in the field of bariatric and metabolic surgery. Many procedures have been described and the field is growing at a rapid pace. It is important to understand that not all bariatric procedures are equal. Not all procedures have the same outcomes. Some also have more complications that can have a negative impact on patients’ quality of life. They also do not have the same academic history and evidence behind them. Some have been preformed for over 50 years and their safety and efficacy are backed by thousands of research articles. Some are much more novel without any real academic data to show where they should fit into the treatment of obesity and obesity related diseases.

[Maybe just a side note here: if your aunt or your neighbour had weight loss surgery thirty years ago and is now suffering major health complications, chances are that they have had a JIB (jejeno ileal bypass). In this procedure the small bowel was transected and a large part was simply bypassed, leaving a long blind loop of bowel with no fluids, enzymes or food passing through that segment. The patient was then left with a short segment of small bowel. This caused two main problems: firstly patients were often left with a small bowel segment that was too short to sustain their nutritional needs. Secondly, patients would develop bacterial overgrowth in the blind loop, which would lead to diarrhoea, liver failure, renal failure and often death. This banned procedure has not been done for a very long time and is not to be confused with the modern bariatric surgery procedures discussed here.]

When I decide which procedures to perform at our unit in general, and which procedure to perform for each patient specifically, there are a number of things that have to be considered. These are the same questions that you can ask when you do your own research about the different bariatric procedures.

As an introduction I usually start with these two questions: What are your expectations? And what are you hoping to achieve through this process? This gives me excellent insight into where the patient is in their journey and why they are considering bariatric surgery. It also helps me to manage the patient’s expectations. When you have a clear answer to these questions in mind, here are some other questions to consider:


First consideration:

You may be tempted to ask: what are the types of bariatric procedures and which one will fit my budget or scares me the least. However, a better first question to ask when deciding on a bariatric procedure is: what are the procedures that are backed by scientific research proving that it is safe and effective? I will give a summary of the answer to this question as it stands in 2023, but you can find an updated list of endorsed procedures on the SAMMSS website:

Procedures that have been performed for more than 20 years (and that have been studied extensively) are the Roux Y gastric bypass (RYGBP), the sleeve gastrectomy and the BPD-DS (billiopancreatic diversion with the duodenal switch).

Building on research from these procedures are the two newer kids on the block: the SADI (Single Anastomosis Duodeno-Ileostomy) and the mini gastric bypass (single/one anastomosis gastric bypass (OAGB)). These two procedures are being performed more and more globally: the SADI has been performed for about 17 years with more and more good long term follow up studies proving its safety and efficacy. The mini gastric bypass has been performed for about 10 years. Early results are promising and both these procedures are now accepted in the treatment of obesity by international bodies like IFSO and ASMBS. A 2022 statement published in the Journal for Surgery for Obesity and Related Diseases concluded that "we anticipate that SADI-S and OAGB will gain popularity in coming years".

Other procedures are mostly still experimental and should really be done in the setting of a clinical trail as part of a structured research protocol.


Second consideration:

A second good question to ask yourself is: how much weight will I loose with bariatric surgery? Every patient is different and we often see outcomes for patients that are not predicted. But it is important to have a realistic sense of what to expect.

Weight Loss (WL) is expressed as a % of Excess Body Weight (EBW). If you loose 100% of your EBW you will reach your ideal weight. The academic literature has shown the following averages:


Average % weight loss







OAGB / mini gastric bypass




Endoscopic sleeve gastroplasty

15-20% (after 2 years, longer data not available)

Gastric balloon


Medical therapy such as Suxenda and Oxempic


From this summary you can see that the BPD-DS has the highest average weight loss. However, is also the most difficult procedure to perform and resulting in the highest number of complications. The follow up after this procedure is also more expensive. This is why it forms only 1% of all performed bariatric procedures worldwide.

This summary gives you a good idea of how to manage your expectations. For instance: if you start with a BMI of 60, and you then have a RYGBP procedure and you end up with a BMI of 40, you have done very well! That is in the range of weight loss that we would normally expect for that procedure.


Third consideration:

“Obese” is not simply a synonym for “fat”. Obesity is a disease that affects the overall health of patients. The primary aim of bariatric and metabolic surgery is not just for the patient to loose weight, but to treat the obesity disease and all its co-morbidities. One can thus not simply ask “how much weight do I want to loose”, but should also ask a third question: “how do I want bariatric surgery to improve my health and quality of life?”.

Broadly speaking bariatric procedures are divided into three categories: restrictive procedures, malabsorptive procedures and thirdly a combination of both of these. When doctors came up with this classification, they did not yet understand the hormonal changes that these procedures induce. Yet these hormonal changes have proven the most important mechanism that induce ánd maintain weight loss following bariatric surgery.

Procedures that do not induce these necessary hormonal changes may result in some weight loss, but it will not necessarily treat the disease of obesity. This includes the endoscopic procedures that are being developed, such as the endoscopic sleeve gastroplasty and the gastric balloon. These procedures are still lacking good long term follow up results. We do not yet know if these modalities will change the end point of the disease of obesity.


Fourth consideration:

Because obesity is a disease, it has to be holistically treated. Bariatric Surgery has proven safe and effective in centres where surgeons work as part of a multidisciplinary team. Such a team usually comprise of a surgeon, a physician or endocrinologist, a dietitian and a psychologist. All these specialists play an important role in the bariatric surgery process. You can not walk into a surgeon’s office today and expect to be in the operating theatre tomorrow. The process takes on average 3-4 months, sometimes longer.

Bariatric procedures are not “one size fits all” and each procedure has certain strengths and weaknesses. It is important to work with a professional team that understands which procedures will be relevant for your unique situation and that can guide you towards making the correct choices.

Ultimately it is important that you choose a team that has experience and is part of their local peer review structures. A good multidisciplinary team will guide you along the path to make the right decision when it comes to surgery, and will assist you in getting the best long term result possible.

There are two bodies in South Africa that oversee the accreditation and peer review of these bariatric multidisciplinary teams: Proventi through SAMMSS (The South African Metabolic Medicine and Surgery Society) and SASSO (South African Society for Surgery, Obesity and Metabolism). When deciding on a team and a surgeon, you can request their accreditation certificate from either of these institutions.

All the best on your bariatric surgery journey!

Dr JGM (Thinus) Smit

Dr Smit is a bariatric and metabolic surgeon at Zuid-Afrikaans Hospital in Pretoria. He is also the general secretary of the South African Metabolic Medicine and Surgery Society (SAMMSS).

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