We invite you to read this informative article about the main features of gastric bypass surgery. We will be as objective as possible by letting you know the advantages and disadvantages of this bariatric procedure to our perspective.


Why is it that we discuss this procedure and not others? The answer is simple, based on statistical figures, globally, we are talking that the gastric bypass along with sleeve gastrectomy are the two most frequently performed bariatric surgical procedures and the reason for this is that they have the best risk/benefit balance.


Before going deeply into this topic we would like to remind you that in our practice we perform much more frequently the gastric sleeve surgery than any other procedure for various reasons, many of which we will discuss in an article dedicated to the gastric sleeve, in  in this article we will talk about the gastric bypass.


According to statistics presented at the IFSO Congress (International Federation for the Surgery of Obesity and Metabolic Disorders) in Montreal in August 2014, for the first time in the history of bariatric surgery, sleeve gastrectomy was the most frequently performed bariatric procedure worldwide displacing the gastric bypass to second place.


The reasons for this new trend may be many, there are several factors that could explain it, however there are no hard numbers or statistics to explain it so on this weight loss surgery blog we will focus on expressing our opinion on these two procedures (bypass on this article and sleeve in a future article) with the aim of helping you as a bariatric patient or potential patient know the most outstanding qualities of these great bariatric procedures which are here to stay, unlike other surgeries appearing and disappearing and being forgotten in less than a decade due to their complexity, high complication rates and/or lack of effectiveness.


Content of this article:
How does the gastric bypass work?
The bypass as a point of reference in bariatric surgery
Statistics on gastric bypass
The dumping syndrome caused by this procedure and its benefits
Advantages of Gastric Bypass
Disadvantages of Gastric Bypass


How does the gastric bypass work?

The explanation of how the gastric bypass and other bariatric procedures work can be extremely complex if we involve their endocrine and gastrointestinal effects, so in order to make the information suitable for every reader we will focus on the basics and practical information.


In bariatric surgery as a treatment option for morbid obesity, there are several procedures that can be "pure or mixed" whether they only reduce gastric capacity (restrictive) or they achieve this in addition to impaired absorption of eaten food (malabsorption).


The gastric bypass is a mixed procedure it reduces the size of the stomach which in turn reduces its capacity and makes an incomplete absorption of ingested nutrients through a malabsorption caused by the “bypass or bridge” of a portion of the gastrointestinal tract.

This procedure achieves a significant weight loss as it helps the patient to eat smaller amounts of food and the food that they eat is absorbed by the body partially.





The bypass as a point of reference in bariatric surgery

Gastric bypass is considered the "gold standard" of bariatric surgery, this means that it is considered as the point of reference and comparison to any other procedure that has been devised, discovered or developed over the last 4 decades, gastric bypass was developed around the early 70's but since its inception until now has had many variations on the technique.


Up to date is a valid and accepted procedure, but, as mentioned previously, with the passage of years its technique has been changed and refined, yet we say refined with some reserve in the sense that since it is more complex than other procedures, exactly the same procedure under the same name can be done in many different ways by two different surgeons, this happens with the purpose of obtaining the best possible results based on their professional experience and the surgical formation they have received, making it difficult to standardize the results obtained in terms of weight loss and complication rates between bariatric groups.


Some advocate leaving a very small stomach "pouch", others consider that the form of the pouch is important, there are those who support the idea that the stomach size is not so important but the length of intestine to "bypass", others consider that the key is the size of the "anastomosis" (junction site between the intestine and stomach) or how this anastomosis is performed.


Anyways, there are countless variations that come into play, so being very objective with this and almost any other bariatric procedure is difficult to standardize the technique and each surgeon has different perspectives on what determines the greater effectiveness of a procedure.


Something that is almost a general concept and accepted by the vast majority of bariatric surgeons is that the effectiveness, outcomes and complication rates justify it as a procedure to be performed laparoscopically and not under the open technique.


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Statistics on gastric bypass

According to statistical data and doing just the comparison between gastric bypass versus gastric sleeve in the effectiveness in losing excess weight, the bypass is superior than the gastric sleeve. The difference varies depending on the report, but is in the range of 5-15% greater weight loss with bypass.


In other words the excess weight loss achieved with gastric bypass varies between 60-75%, while the gastric sleeve, depending on the publication goes from 60 to about 70%. It is difficult to say with certainty because the involved factors that determine these numbers are several. If these numbers are trustable, it could be said that there is no big difference in effectiveness between the two procedures.


It is important to emphasize that neither bypass or sleeve gastrectomy or duodenal switch or any existing bariatric procedure so far, achieves the excess weight loss of 100%, which is why in other articles we insist so much that as a patient or potential patient, you should see any bariatric surgery as a tool and not as a "simple" solution to obesity problems.


If you want to know more about the different options that exist within weight loss surgeries and another options, we invite you to visit our article on MORBID OBESITY TREATMENT OPTIONS . Having this knowledge will allow you as a patient know that undergoing a bariatric procedure is synonymous with a commitment with yourself considering the investment required in time, money and above all health.


Gastric bypass is, as previously mentioned, one of the procedures that have stood the test of time and has been performed for decades with good success rates.


With the advent of laparoscopy and its establishment in the last two decades as an integral part of training surgeons, the percentage of complications became equal to open bypass surgery and now that percentage is even lower in certain groups than those obtained with open technique. It is calculated that the rate for major complications for the gastric bypass is about 3 to 3.5% and 20-25% for minor complications. The incidence of mortality is about 0.5%.



The dumping syndrome caused by this procedure and its benefits


Because gastric bypass surgery causes dumping syndrome, it is a very good procedure (at least initially) for patients whose obesity problem is mainly due to their "weakness" to high calorie food based on carbohydrates and refined sugars, some examples are chocolate, ice cream, milkshakes, candies, bread, etc.


The reason for this is that the dumping syndrome causes the patient to experience one or more symptoms after eating these foods, (eg: tachycardia, nausea, vomiting, abdominal pain and/or abdominal distention, etc.) symptoms that are sufficiently unpleasant to the patient that he/she chooses to avoid them, which in the long term, in theory, helps weight loss to be maintained and leads the patient to eat food with better nutritional value. Gastric emptying symptoms are diverse and can be reviewed in our article concerning to this topic.


Why do we mention that "at least the syndrome is initially present and in theory helps weight loss"? Because unfortunately many patients, after a few months or years manage to develop a progressive tolerance to these high calorie/carbohydrate foods to the point that such dumping syndrome no longer occurs, if this happens, obviously the effectiveness is lost in that patient on making him/her to avoid this kind of food.


Nevertheless, back to the same, a patient that after several months (lets say 12 to 18 months after surgery) has failed to change eating habits and continues to test his/her surgery and investment, is a patient who has not understood the concept of bariatric surgery (or was not properly instructed) and eventually the lost weight will be recovered, and talking about gastric bypass probably gain it back almost entirely and could even weigh more than before the surgery. This is considered a total failure of surgery which may be due to a combination of poor patient selection by the surgeon and the procedure.



Advantages of Gastric Bypass


  • Greater weight loss than with gastric sleeve


  • It is a mixed procedure (restrictive and malabsorptive)


  • Better diabetes control


  • Has been performed for more than 4 decades


  • Extensive experience in the results in the short, medium and long term



Disadvantages of Gastric Bypass


This procedure involves risks of:


  • Anastomotic ulcers (junction created between intestine and stomach)
  • Internal hernias / bowel obstruction
  • Gastric pouch enlargement with subsequent weight regain
  • Malnutrition
  • Anemia
  • Vitamin deficiencies
  • Chronic diarrhea
  • Very smelly stools and flatulence
  • Need for regular checkups and laboratory tests (cost and tedium)
  • Difficulty for revision or conversion to another procedure
  • Possibility of regaining weight to the extent of surpassing the initial weight
  • "Ash" appearing skin in most patients
  • Because of its complexity can have many variants from surgeon to surgeon
  • Increased risk of complications in the short, medium and long term


As you can see there are many reasons to think that gastric bypass is not the best option as weight loss surgery treatment, yet although there are definitely details to consider, it is still currently the second most performed bariatric procedure in the world, the benchmark for any bariatric procedure and in which there is more experience in terms of the time it has been performed worldwide.


Moreover, despite the long list of disadvantages, many of them are just possibilities and not necessarily will be present and the fact that continues to have such popularity talks about the good results achieved in relation to weight loss and health on those who decide to have this procedure.


So if your bariatric surgeon recommends this procedure and you're a good candidate for it, do not doubt that it will bring many benefits in the long term, you just have to be aware that you must never forget you had this procedure done in order to have the proper follow up for lifetime.


Finally, seeking to avoid confusion with the terminology, this procedure is known by different names: gastric bypass, gastric by pass, RNY, Roux en Y, etc.


Your turn, tell us what you think of this procedure, if you are planning to have this or any other weight loss surgery and which one?


If you are interested in having your surgery of gastric sleeve in mexico, contact us at info@obesityfree.com



Written by: Gabriel Rosales

Dr. Gabriel Rosales is a highly skilled, board certified surgeon in constant pursuit of learning the latest innovations in the weight loss surgery field to give his patients the best care possible.