Weight loss

Your Intro to Weight Loss Surgery Options

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Medically approved by Dr Earim Chaudry
Chief Medical Officer
iconLast updated 26th February 2022

In 30 seconds

Weight loss surgery can be a good option for patients who are severely obese, as well as those who suffer from obesity-related health conditions. While risks exist, they tend to be outweighed by those of obesity itself. In terms of weight loss outcomes, gastric bypass surgery is most effective — but it also comes with higher risks of complications. Gastric sleeves, bands, and balloons are alternatives.

An Intro to Bariatric Surgery

Bariatric surgery — also called metabolic surgery — is a broad term that includes any surgery to the digestive system for the purpose of promoting weight loss.

It is typically only recommended for patients who:

  • Are classified as severely obese. That means that their Body Mass Index, or BMI, is over 40.

It may also be recommended for those who have a BMI over 35 combined with other health complications, such as sleep apnoea and type 2 diabetes.

To work out your BMI, divide your weight in kilograms by your height in metres squared:

BMI = kg/m2

The NHS offers this handy calculator that will do the maths for you.

  • Have exhausted other weight management methods, such as diet and exercise.
  • Are happy to make a long-term commitment. This means a combination of post-surgery check-ups and follow-up lifestyle interventions.

Benefits of Weight Loss Surgery

Most patients are able to lose weight through bariatric surgery and keep it off for at least four years after surgery. It’s currently the most effective treatment for extreme obesity.

According to this study, candidates undergoing bariatric surgery lost five kilograms more in each of the following months after the surgery than the group who didn’t undergo surgery.

Added to this, if you are a good candidate for this type of surgery, it can yield results not only in terms of weight loss but also in its impact on various other health conditions.

For example, weight loss surgery may help treat the following conditions, as well as prevent them from developing in the future:

  • type 2 diabetes
  • high blood pressure
  • sleep apnoea
  • heart disease
  • high cholesterol
  • arthritis.

Risks of Weight Loss Surgery

For patients who are severely obese, the risks posed by their current weight are typically greater than having the surgery.

But bariatric surgery is certainly not without its dangers — and it’s definitely not a quick fix option. It has to be followed up with lifestyle changes, as well as continual check-ups with your doctor.

In one study, fewer than 1% of patients died within 30 days of having the surgery. In this recent study of Swedish patients who had undergone bariatric surgery, having the surgery prolonged life expectancy.

But there are still risks that you should be aware of. The most common are:

  • Blood clots in the legs and lungs. If you experience pain, swelling or redness in the legs any pain behind the kneecap, or swelling or redness in the back of your leg after an operation, it’s important to notify your doctor urgently.
  • Struggling to get enough vitamins and minerals from your diet. It’s likely that you will have to take supplements for the rest of your life. 
  • Extra folds of skin. There are surgery options available to remove these, but they can be very risky.
  • Gallstones. These occur when bile in the gallbladder hardens into little stones. This is a danger with any rapid weight loss, including bariatric surgery. In this study of 96 patients undergoing laparoscopic sleeve gastrectomies, the incidence of gallstone formation was 47.9%. They usually happen within 18 months of the procedure.

To optimise your chances of favourable outcomes, the aftercare recommendations include doing 150 minutes of physical activity a week (which will ideally build up to 300 minutes a week), avoiding or reducing alcohol consumption, and stopping smoking.

Types of Weight Loss Surgery

There are several possibilities depending on the needs of the patient:

Gastric Bypass Surgery

Also known as a “Roux-en-Y” gastric bypass, this common weight loss procedure involves dividing the stomach into two pouches — a smaller upper one and a much larger lower one. The small intestine is then cut and rearranged. The smaller stomach pouch is connected back to the rest of the small intestine.

Because of this new configuration, food will bypass your stomach, meaning you do not absorb as many calories as you would otherwise and you feel full much quicker than before.

Unfortunately, there is a risk of leakage at the connection points if they do not fully heal. This happens in about 1.5% to 6% of surgeries and can cause infection and internal bleeding. 

If you experience pain, fever, nausea or vomiting, or drainage from your wound, it’s important to get to your doctor as soon as possible.

In this study, gastric bypass surgery was found to be highly effective as a weight loss strategy, but it was more dangerous than other methods in terms of potential complications.

Sleeve Gastrectomy

A sleeve gastrectomy involves separating and removing part of the stomach. What is left of the stomach is then tied into a tube. As a result, the stomach becomes about 15% of its previous size.

Because it can no longer hold as much food, you will not be as hungry and will feel satiated more quickly. The smaller stomach will also produce less of a hormone called ghrelin, also known as the “hunger hormone.” This may decrease your desire to eat.

Complications from sleeve gastrectomies are half as likely as they would be with gastric bypass surgery, meaning it may be a safer option to consider. But that doesn’t mean there aren’t risks.

Along with complications such as internal bleeding, blood clots, gallstones, and gastric leakage. This can be very dangerous and put your organs at risk. Fever and a rapid heartbeat are the most common signs of these complications. 

Gastric Band Surgery

The goal of gastric band surgery is also to decrease the size of the stomach so that food intake is limited. In this method, an inflatable silicone band is placed around the upper portion of the stomach and a tube is attached to it.

The bariatric surgeon then injects saline solution into the band so that it inflates. This creates a separation of the stomach into two separate pouches, which makes you feel fuller, faster.

It’s less invasive than other forms of gastric surgery in the sense that there is no cutting and separating of the digestive system, but it is not without its risks.

There is a chance that the gastric band can slip out of place, blocking the gastrointestinal system or causing food to leak out of the digestive tract.

It’s less common than other methods like gastric sleeve and bypass surgeries, but may be appropriate in some cases. 

Intragastric Balloon

A method that is gaining in popularity is the intragastric balloon. A saline-filled silicone balloon is placed in the stomach, limiting the amount of food it takes to feel full.

It’s not permanent and is done without surgery. The balloon is inserted through your oesophagus and into your stomach and then inflated.

The gastric balloon has a complicated history, but recent developments have meant that it has real potential as a weight loss intervention and could be used before trying other, more invasive procedures. 

One risk is that the balloon can deflate and move through your digestive system, causing a blockage. If this happens, you might require additional surgery to remove it.

Biliopancreatic Diversion with Duodenal Switch (BPD/DS)

BPD/DS is a less common option that is made up of three parts:

  1. First, gastric sleeve surgery is performed, in which part of the stomach is removed.
  2. Then the stomach is connected to the lower part of the small intestine, rerouting food away from the upper part.
  3. A different part of the stomach is removed. This changes how bile and digestive juices break down food. The result is that the body does not absorb as many calories and nutrients as before.

One of the biggest risks is that you will not be able to absorb as many nutrients after the procedure. You could have deficiencies of iron, protein and various vitamins, including A, D, E and K, which could be dangerous for your health.

Because it is a risky procedure, it’s usually only recommended for people with a BMI over 50.

Key Takeaways

Bariatric surgery is a weight loss option for patients struggling with severe obesity and/or complications that result from obesity. But it won’t work all by itself. It should always be considered only alongside lifestyle interventions, such as a healthy diet and exercise/physical activity.


What is the Weight Limit for Weight Loss Surgery?

Rather than a weight limit, eligibility for weight loss surgery is deduced by BMI. Severely obese patients with a BMI over 40 are typically good candidates. If your BMI is between 35 and 40, and you also have an obesity-related health condition such as diabetes or high blood pressure, you may also be considered for a procedure. 

How Much Does Surgery for Weight Loss Cost?

For people who meet certain criteria, weight loss surgery is available on the NHS. You can also pay for it privately. Depending on the type of surgery you have, bariatric surgery costs somewhere between £4,000 to £15,000 in the UK. 

  • Gastric bypass surgery is usually £8,000 to £15,000.
  • Gastric band surgery is usually £4,000 to £8,000.
  • Gastric sleeve surgery is usually £8,000 to £10,000.

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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