Insights into gastric bypass surgery

Written by: Mr George Vasilikostas
Edited by: Carlota Pano

Gastric bypass surgery, also known as Roux-en-Y gastric bypass, is an effective bariatric (weight loss) surgical procedure involving both restrictive and malabsorptive techniques to help achieve weight loss.


Here, Mr George Vasilikostas, renowned consultant general, gastrointestinal and bariatric surgeon, delves into the mechanisms of gastric bypass surgery.



What does a gastric bypass procedure entail?


A gastric bypass procedure is one of the commonest weight loss procedures. It has been around for more than 50 years and it has a proven safety efficiency, providing excellent results in terms of weight loss and quality of life.


Nowadays, a gastric bypass is performed almost exclusively via keyhole laparoscopic surgery. The basic principle of the procedure involves creating a small gastric pouch, by disconnecting the proximal part of the stomach from the distal part and then joining the small bowel with the small gastric pouch in order to be able to drain it.


With this configuration, food bypasses the whole distal stomach, the duodenum, and the first part of the bowel. As a result, undigested food travels straight to the bowel, triggering signals from the gut to the brain which is responsible for the body’s metabolic response. Changing these signals can reset metabolism, and this is why a gastric bypass is one of the most effective weight loss surgery procedures nowadays.


Is a gastric bypass considered major surgery?


I would say that a gastric bypass isn’t considered a major surgery anymore. The procedure does involve general anaesthetic, but this is extremely safe.


The typical hospital stay after a laparoscopic gastric bypass is one or two days. In selective low-risk patients, the procedure can even be performed as day case surgery.


The complication rate is also quite low, matching any other commonly-performed abdominal surgery like, for example, appendicectomy or cholecystectomy. There have been studies showing that the serious events from a gastric bypass surgery are pretty much the same as any other medical treatment that includes medication and lifestyle modifications.


Additionally, the risk of mortality for a gastric bypass is extremely low, below 1.1 – 1.2%. According to data from the National Bariatric Registry, the risk may even be well below this level.


Is a gastric bypass a painful procedure?


A laparoscopic gastric bypass is very well tolerated. Patients may feel mild to moderate amounts of abdominal discomfort or pain for the first one or two days, alongside a minimum amount of nausea, but this typically resolves soon.


The overall recovery process is also very straightforward. Obviously, patients will need to adhere to a special diet post-op, but other than that patients will pretty much be back to normal activities after one or two weeks.


How soon will I lose weight after undergoing gastric bypass surgery?


What is interesting is that, for the first few weeks to three months, the rate of weight loss after gastric bypass surgery is very quick and very impressive. During this period, patients can lose 15% -20% of their total weight or 30% of their excess weight.


Weight loss then typically continues after six months. Following this period, some patients will continue to lose weight for one, one and a half, or two years. Other patients will start to plateau in terms of weight loss within one year.


How successful is a gastric bypass? Could I regain the weight?


Gastric bypass surgery has proven its efficiency in the long term, helping patients lose 35% of their total weight or 60% - 70% of their excess weight in total following the procedure. Obviously, the response to a gastric bypass can vary, as with any other treatment for any other disease, but overall results suggest that patients can sustain their weight loss in the long term.


We also encourage patients, along with gastric bypass surgery, to engage with their healthcare team in order to implement positive behaviour and dietary changes that will optimise results and prevent weight regain in the future.



If you are considering gastric bypass surgery and would like to consult your options with an expert, schedule a consultation with Mr George Vasilikostas via his Top Doctors profile today.

By Mr George Vasilikostas

Mr George Vasilikostas is a leading consultant general, gastrointestinal and bariatric surgeon based in London. With more than 25 years of experience, Mr Vasilikostas is highly experienced in a wide range of surgical procedures with a focus on laparoscopic upper GI and bariatric surgery. His areas of expertise include weight loss surgery, gastric bypass, intra-gastric balloon, acid reflux surgery and gallbladder surgery.

Mr Vasilikostas first graduated with an MD from the University of Athens School of Medicine in 1998, before going on to receive a PhD from the same institution in 2008. Since qualifying, he has completed a number of prestigious surgical fellowships and has worked at some of Europe’s most renowned hospitals.

Mr Vasilikostas has a special interest in advanced laparoscopic surgery, perfoming complex procedures such as laparoscopic oesophagogastrectomy, as well as bariatric surgery for super-obese patients.

In addition to his clinical work, he is also revered for his medical research, having published numerous articles in peer-reviewed scientific articles. His surgical expertise led him to become a faculty member of various medical courses at both St George’s and the Royal College of Surgeons of England. 

View Profile

Overall assessment of their patients

  • Related procedures
  • Laser
    Laser scar therapy
    Surgical dermatology
    Hair transplant
    Scar revision
    Facial surgery
    Chin surgery (mentoplasty)
    Breast augmentation with implants
    Breast fat transfer
    This website uses our own and third-party Cookies to compile information with the aim of improving our services, to show you advertising related to your preferences as well analysing your browsing habits. You can change your settings HERE.