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Gastric Sleeve Surgery​

This powerful form of weight loss surgery can help patients to lose up to 70% of excess body weight.  

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By Mr Rishi Singhal MBBS, MRCS, FRCS, MD

Last review: 09/05/2022. All content on this page is reviewed by a multi-disciplinary team lead by Mr Rishi Singhal.

Gastric Sleeve Surgery Overview

What is the gastric sleeve?

The gastric sleeve (laparoscopic sleeve gastrectomy) is the world’s fastest-growing weight loss procedure. Gastric sleeve surgery has grown rapidly in popularity in recent years and now accounts for more procedures in the NHS than gastric band or gastric bypass surgery.

The gastric sleeve is a simple yet effective concept. We access the abdomen laparoscopically (keyhole surgery) and make small incisions in the stomach along its length and remove about 80%, creating a smaller stomach. After gastric sleeve surgery, the food you eat will still enter and exit the stomach in the same place as it did before (unlike the gastric bypass) but you’ll have a much smaller stomach.

The gastric sleeve helps you lose weight in two ways.

  1. It reduces the capacity of your stomach by around 80%, so you can only eat smaller amounts of food and feel full quicker. 
  2. It changes the balance of hormones and proteins in the stomach. The Hunger hormone ghrelin is removed resulting in a change and suppressing appetite. For this reason, we expect sleeve patients to lose weight quickly after gastric sleeve surgery.

It’s important to note that your weight loss isn’t directly related to the size of your remaining stomach. The change to gut hormones will facilitate weight loss whether you have a relatively ‘tight’ or ‘loose’ sleeve.

After gastric sleeve surgery, we expect most people to lose between 60 and 70% of excess weight. This type of weight loss surgery has also helped people with obesity-related long term health conditions such as type 2 diabetes and PCOS. 

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At a high level we can say that the combination of restriction (a smaller stomach) and changes to the gut hormones are the cause of the weight loss after gastric sleeve surgery.

When we look more closely, there are three effects that we know about in relation to the change in gut hormones. 

  • Ghrelin – we know that when the sleeve is done the amount of ghrelin produced by the body reduces.
  • Bile acid metabolism – we also know that there are changes in the way that body metabolises bile acid
  • Gut micro biome – Probably the biggest factor, and the one we currently know least about, is a change in the gut micro biome – changes to the bacteria in the gut. 

The combination of these factors will both reduce and change the appetite of the majority of patients so that about 90% are successful with sleeve surgery. Patients will often say that their taste for food changed immediately.

As with all weight loss surgery though, the key to long term success is to embed the right diet and eating habits in the years immediately after surgery in order that you can sustain those behaviours long term, when we know the immediate benefits of the procedures will start to diminish. So, aftercare and support are just as important for sleeve patients as they are for those who have the other weight loss procedures.

Am I eligible for the gastric sleeve?

To be eligible for a gastric sleeve you must have a BMI of at least 35. 

The eligibility criteria that apply in private healthcare are a little different than those that apply in the NHS.

The reason is that the NHS eligibility criteria that is set by NICE (the National Institute for health and Clinical Excellence) has to balance the public health benefit with what the state can afford. 

In the private sector we are not faced with the same price restraints as patients are paying for their own procedure. This means that we can take decisions based purely on the available scientific data. For that reason we will generally consider patients with lower BMI than would be the case for the NHS.

The NICE guidelines state that patients will be eligible for weight loss surgery if they have a BMI above 40 or above 35 with at last one major co-morbidity. In addition patients will ned to follow and ‘pass’ a 6 – 12 month weight loss programme before they will be considered eligible for surgery. There will then usually be a waiting list.

The reality is that very few NHS Trusts apply these criteria and you may have read in the press that Trusts are applying their own, much tighter, selection criteria. This is because they do not have the resources needed to apply the NICE guidelines.

Some Trusts are limiting surgery to patients with a BMI over 50, to diabetics and/or to patients who don’t smoke.

At Healthier Weight, we generally consider sleeve surgery for patients with a BMI of 35 and above. You will need to have tried and failed with diets as a way to manage your weight and your weight will need to be having a negative effect on your every day life.

If you are of Asian ethnicity and/or you are a Type 2 diabetic we would consider surgery at a lower BMI. We will explain the eligibility criteria in more detail at your face to face consultation.

How Long Is Gastric Sleeve Surgery

Gastric sleeve surgery will usually last between 45 and 60 minutes. Usually 4, sometimes 5, small horizontal incisions will be made in the stomach through which the instruments are passed. These incisions will leave small scars that are usually about 5mm long, so very small.

You’ll stay in a hospital for a short period, usually 2 nights, and will then be discharged home where you’ll be encouraged to rest for at least 7 days to allow your body to recover.

Read more about the gastric sleeve operation here

How much weight will I lose with the gastric sleeve?

The primary reason most patients choose gastric sleeve is to lose weight. It’s a very powerful procedure and most studies show average (mean) excess weight loss of 60-70%* over a 2 year period. Some studies show even better weight loss results but we think this is a reasonable expectation. One of the attractions is that the weight is usually lost as quickly, as the procedure reduces and changes appetite. You’ll see in our patient success stories section that people achieve spectacular results with the sleeve.

Of course, to maintain the weight loss for the long term it’s important to make changes to your diet and exercise habits so that you can maintain your weight loss in later years should the ‘power’ of your sleeve begin to diminish.

Success Stories

Real People, Real Stories, Real Lives Changed With The Gastric Sleeve

Benefits & Risks

What are the health benefits of gastric sleeve surgery?

The gastric sleeve is the fastest growing weight loss surgery procedure in the world because it delivers excellent weight loss results and improvements to health. The knock on effect of both is that it also helps patients achieve an improved quality of life.

Here are the benefits you can expect from your sleeve surgery. These are taken from respected scientific journals and the relevant publications are shown at the foot of this page.

Type 2 Diabetes

The sleeve is an excellent procedure for diabetics and 80% of patients can expect a complete resolution of their symptoms

Raised Blood Pressure (Hypertension)

85-90% of patients who are taking medication to reduce their blood pressure can expect top stop medication altogether.

Sleep Apnoea

Patients see improved sleep patterns and reduced fatigue. Over 85% of patients who use a CPAP machine will be able to stop.

Infertility and PCOS

A very important consideration for some sleeve patients is that they want to lose weight to start or grow their family. Over 90% of sleeve patients improve their underlying hormonal well-being and restore fertility.

Back Pain and Arthritis

An important consideration for many patients is that their weight is being to impact on their mobility and is causing joint pain. The sleeve can help this by reducing the load that joints are bearing. Studies show that patients report increased mobility after sleeve surgery.

Mental Wellbeing

This is a very important benefit of the gastric sleeve. Often, patients have been dealing with mental health issues associated with their weight for many years. Studies show that sleeve patients report a reduction in anxiety and depressive symptoms. They also report a significant improvement in overall quality of life.

We pay great attention to mental health in our pre-operative assessment process. There is evidence to show that suicide among weight loss surgery patients is higher than in the general population. This is a complex area and there will be many possible reasons for this. One is that some patients have developed a ‘dependency’ on food and when that is removed it will transfer elsewhere sometimes to alcohol or drugs. Our pre-operative screening process is designed to ensure long-term mental well-being for our weight loss surgery patients. Our programme was developed by Dr Claire Parkes, Psychologist.


There are other health benefits, for example in respect of Asthma and liver disease but we have not listed all of them here. If there is a health problem we have not listed that you wish to enquire about, please call us and we’ll be happy to discuss it with you.

What are the risks of gastric sleeve surgery?

As with any surgery, there are operative and long-term complications and risks associated with gastric sleeve obesity surgery but in experienced hands, the procedure is very safe and the risks associated with the surgery are relatively small. The operation itself is technically very simple as it does not involve any cutting or joining of the bowel, unlike some other weight loss procedures such as the gastric bypass, and this is reflected in its low rate of early complications of 3 – 5% (3:100 to 5:100) and in the low mortality rate of 0.1 – 0.5% (1 in 1000 to 5 in 1000).

Gastric sleeve risks include:

  • Haemmorrhage (bleeding) 
  • Leaks from staple lines leading to infection 
  • Adverse reactions to anaesthesia and/or medication 
  • Blood clots (Deep vein thrombosis in the legs / Pulmonary embolus on the lungs) 
  • Longer term, potential nutritional deficiency 
  • Marginal ulcer 
  • Narrowing of the stomach

Read more about the common complications of gastric sleeve surgery


Cost & Finance

Gastric sleeve cost and finance

The fixed price of your gastric sleeve will vary depending on several factors including your location, your surgeon and any special treatment requirements that are identified at your consultation. For example, do we need to schedule a night in the high dependency unit for you (this would only apply to patients with significant weight related health issues).


We offer 2 finance packages to pay for your gastric sleeve procedure. Click below to compare monthly payments.


The importance of great aftercare is often underestimated when it comes to gastric sleeve. Most patients enjoy excellent weight loss in the first year or two but some weight regain is quite common after a few years. This can be reduced by adopting the correct dietary and exercise habits in the first couple of years after surgery.


Get well on your way with all the essential rolled into one package
  • Lifelong support
  • 1 surgeon review when medically indicated
  • Virtual clinic review with specialist bariatric nurse at 12 months
  • Blood tests at 6 months
  • Long term follow up calls:
    3 days, 10 days, 3 weeks, 2 months, 3 months, 6 months, 12 months, 18 months & 24 months
  • 12 months access to the Healthier Weight platform/app
  • 1 x 1-2-1 appointments with dietician*


Our most comprehensive aftercare package with live support for 2 years
  • Lifelong support
  • 1 surgeon review when medically indicated
  • Virtual clinic review with specialist bariatric nurse at 12 months
  • Blood tests at 6 months
  • Long term follow up calls:
    3 days, 10 days, 3 weeks, 2 months, 3 months, 6 months, 12 months, 18 months & 24 months
  • 24 months access to the Healthier Weight platform/app
  • 4 x 1-2-1 appointments with dietician*
  • Set of WiFi scales
  • 1-2-1 appointment with health coach*
Save £600


Extra nutritional advice from an expert bariatric dietitian
  • Lifelong support
  • 1 surgeon review when medically indicated
  • Virtual clinic review with specialist bariatric nurse at 12 months
  • Blood tests at 6 months
  • Long term follow up calls:
    3 days, 10 days, 3 weeks, 2 months, 3 months, 6 months, 12 months, 18 months & 24 months
  • 18 months access to the Healthier Weight platform/app
  • 2 x 1-2-1 appointments with dietician*
  • Set of WiFi scales

*Hosted on the Healthier Weight app


Gastric sleeve common FAQs

As with all surgical operations, there are associated risks and a gastric sleeve is a more invasive procedure than a gastric band which is why it is important to choose a specialist bariatric surgeon with considerable gastric sleeve experience. In the hands of a highly experienced Healthier Weight surgeon, the gastric sleeve is still a safe and effective procedure. Read more about our sleeve centres and surgeons here.

Due to the considerable amount of weight that gastric sleeve patients typically lose, it’s possible that you will experience some excess, loose or saggy skin. This most commonly occurs in the abdominal apron, or trunk area. The amount of excess skin you’ll be left with following a gastric sleeve operation varies and will depend upon your age and weight before the procedure. Generally, the heavier and older you are, the more likely you are to have excess skin. Younger patients tend not to have as much lax skin due to greater natural skin elasticity. 

On average we expect weight loss results for gastric sleeve patients to be approx 60-70% of their excess weight during the first two years, although most of the weight is lost during the first year. Some people will inevitably do better than this, and some not so well.

Most sleeve patients will stay in a hospital for 2 nights before going home. You should start to feel much more comfortable around 2 weeks after surgery, but it typically takes around 6-8 weeks for your stomach to heal completely.

You can eat most foods, providing they don’t cause you discomfort. However, because you will be consuming less food in general, it is important that you include foods that are rich in protein, but low in fat and sugar. We encourage you to eat vegetables, fruit, wholegrains, lean meat and fish. You will be provided with detailed nutritional information following your gastric sleeve operation.

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*Surg Obes Relat Dis. 2011 Nov-Dec;7(6):749-59. doi: 10.1016/j.soard.2011.07.017. Epub 2011 Aug 10. Third International Summit: Current status of sleeve gastrectomy

Mr Rishi Singhal MBBS, MRCS, FRCS, MD

Mr Rishi Singhal MBBS, MRCS, FRCS, MD

Mr Singhal is an expert bariatric surgeon based in the West Midlands and also Medical Director at Healthier Weight

Call our specialist team today on
0800 313 4618 
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