Weight loss surgery is available on the NHS for people who meet certain criteria.

It's also available privately, but you'll have to pay for it and it can be expensive.

NHS criteria for weight loss surgery

The criteria for weight loss surgery on the NHS can vary across England. Check with your GP if you think surgery could be an option for you.

National Institute for Health and Care Excellence (NICE) guidelines on obesity recommend that surgery should be provided on the NHS if you meet all of the following criteria:

• you have a body mass index (BMI) of 40 or more, or a BMI between 35 and 40 and a serious condition that might improve if you lost weight (such as type 2 diabetes or high blood pressure)
• you've tried all other weight loss methods, such as dieting and exercise, but have struggled to lose weight or keep it off
• you agree to long-term follow-up after surgery – such as making healthy lifestyle changes and attending regular check-ups
• you're fit and healthy enough to have surgery under general anaesthetic (where you're asleep)
• you've been receiving or will receive treatment from a specialist obesity team

If your BMI is 50 or over, surgery may be considered without needing to try other weight loss methods first.

If you've been diagnosed with type 2 diabetes recently, particularly if you have a South Asian background, an assessment to see if surgery is suitable may be considered if your BMI is below 35.

Private weight loss surgery

The cost of private weight loss surgery can vary.

Typical prices are:

• gastric band surgery – £4,000 to £8,000
• gastric bypass – £8,000 to £15,000
• sleeve gastrectomy – £8,000 to £10,000

You may not need a referral from your GP for private treatment, but it's a good idea to speak to them for advice first.

Before approaching a private clinic or surgeon, do as much research as possible into the different types of weight loss surgery and think about the questions you want to ask.

Some people consider having treatment abroad, where costs for private treatment can be cheaper, but make sure you weigh up any potential savings against the potential risks.

Standards may not be as strict when outside the UK and aftercare isn't always straightforward. Some clinics may not provide follow-up care either at all or up to the same standard as in the UK.

There are several different types of weight loss surgery.

They're all usually done under general anaesthetic (where you're asleep) using keyhole (laparoscopic) surgery, but they each work in a slightly different way.

Keyhole surgery is where a surgeon makes small cuts in the tummy and inserts a flexible viewing tube so they can see inside while they perform the operation.

Main types of weight loss surgery

Gastric band

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Monica Schroeder/SCIENCE PHOTO LIBRARY

A gastric band is a band that's placed around the stomach, creating a small pouch towards the top.

It takes less food to fill the pouch, so you don't need to eat as much before you feel full.

The band is connected to a small device placed under the skin (usually near the middle of the chest). This is so the band can be tightened after surgery.

The band will usually be tightened for the first time about four to six weeks after surgery. This is done by injecting the device with salt water solution using a needle passed through your skin. You don't usually need any anaesthetic for this.

The band will need to be tightened a few times to get to the ideal tightness for you.

Gastric bypass

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JACOPIN/BSIP/SCIENCE PHOTO LIBRARY

A gastric bypass is where surgical staples are used to create a small pouch at the top of the stomach.

The pouch is then connected to your small intestine, missing out (bypassing) the rest of the stomach.

This means it takes less food to make you feel full and you'll absorb fewer calories from the food you eat.

Sleeve gastrectomy

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JACOPIN/BSIP/SCIENCE PHOTO LIBRARY

A sleeve gastrectomy is where a large part of the stomach is removed so it's much smaller than it was before.

This means you can't eat as much as you could before surgery and you'll feel full sooner.

Intra-gastric balloon

An intra-gastric balloon is a soft balloon filled with air or salt water that's placed into your stomach using a thin tube passed down your throat (known as a gastroscopy).

This means you won't need or be able to eat as much before you feel full. But it's only a temporary measure and the balloon is usually left in for a maximum of six months.

Biliopancreatic diversion

A biliopancreatic diversion is similar to a gastric bypass, except the stomach pouch is connected further along the small intestine.

This means you'll absorb even fewer calories from the food you eat. But it can cause more side effects than a gastric bypass, so it's less commonly used.

Which type of weight loss surgery is best?

All types of weight loss surgery can help you lose a significant amount of weight, but they each have advantages and disadvantages.

For example:

• you usually lose weight more quickly after a gastric bypass or sleeve gastrectomy than after gastric banding
• more people tend to achieve significant weight loss with a gastric bypass or sleeve gastrectomy than with a gastric band
• the risk of serious surgery complications is generally higher for a gastric bypass or sleeve gastrectomy
• gastric bands are removable, so the operation can be reversed if it causes serious problems

If you're considering weight loss surgery, talk to your surgeon about the different techniques to decide which is best for you.

Assessment before weight loss surgery

Before weight loss surgery can take place, you'll be referred to a specialist clinic for an assessment to check if the operation is suitable.

This may involve checks of your:

• physical health – such as blood tests, X-rays and scans
• diet and eating patterns
• mental health – such as asking about your expectations of surgery, and whether you have any mental health conditions; this is to assess if you'll be able to cope with the long-term lifestyle changes needed after weight loss surgery

You may be advised to have a calorie-controlled diet in the weeks before surgery to help reduce the size of your liver. This can make surgery easier and safer.

You can usually leave hospital one to three days after weight loss surgery and start to return to your normal activities four to six weeks later.

But you'll need to make long-term lifestyle changes to help make the most of your surgery.

Diet after weight loss surgery

You'll be given a diet plan to follow after surgery.

These vary from person to person, but a typical plan is:

• first few days – water and fluids (for example, thin soup)
• first four weeks – runny food (for example, yoghurt or puréed food)
• weeks four to six – soft food (for example, mashed potato)
• week six onwards – gradually return to a healthy, balanced diet

You will also be advised to:

• eat slowly, chew carefully and only eat small amounts at a time – particularly during the early stages of your recovery
• avoid or be careful eating foods that could block your stomach, such as soft white bread
• take vitamin and mineral supplements

The charity WLS Info has more information about eating after your operation.

Exercise after weight loss surgery

As well as eating healthily, you'll need to exercise regularly to help you lose as much weight as possible after the operation.

You may be given an exercise plan. This will usually involve increasing your activity levels gradually as you recover from surgery.

Once you've fully recovered, you should aim to do regular activities that are intense enough to leave you feeling out of breath and make your heart beat faster, such as: 

• brisk walking
• cycling
• gardening or housework
• swimming

Choose something you enjoy as you'll be more likely to stick with it.

Read more about getting fit and tips for people starting exercise. The British Obesity Surgery Patient Association (BOSPA) also has information about exercise after weight loss surgery.

Follow-up appointments

After weight loss surgery, you'll be asked to attend regular follow-up appointments for the rest of your life.

These appointments will usually be in a weight loss surgery clinic for at least the first two years, but eventually you may just need a check-up with your GP once a year.

Follow-up appointments may involve:

• blood tests to check your vitamin and mineral levels
• a check-up of your physical health
• advice and support about diet and exercise
• emotional or psychological support

Pregnancy and contraception after weight loss surgery

Women are usually advised to avoid becoming pregnant during the period of most significant weight loss in the first 12 to 18 months after surgery.

This is because weight loss surgery can affect your vitamin and mineral levels. If your levels are low while you're pregnant, there's a risk it could harm your baby.

It's a good idea to:

• use contraception until advised it's safe to become pregnant – ask your doctor about the best type, as some aren't suitable for women who've had weight loss surgery (including the contraceptive pill and contraceptive injection)
• speak to your doctor if you become pregnant soon after surgery or you're planning a pregnancy at any stage after surgery – they can check your vitamin and mineral levels, and advise you about supplements (find out about vitamins and nutrition in pregnancy)

Help and support

Having weight loss surgery can be physically and emotionally draining.

Support will be provided as part of your follow-up, but you may also find it useful to talk with people who have also had weight loss surgery.

Ask your specialist about any charities and support groups in your area or check the WLS Info website.

When to get medical advice

In the days or weeks after surgery, call your GP or NHS 111 immediately if you have:

• pain in your tummy that's really bad, doesn't go away or is getting worse
• an unusually fast heartbeat
• a high temperature (fever) of 38C (100.4F) or above
• chest pain or shortness of breath
• repeated vomiting or vomiting blood
• difficulty swallowing
• dark, sticky poo
• signs of a wound infection, such as pain, redness, swelling and pus

In the months after surgery, make an appointment to see your GP if you:

• have pain in your tummy that comes and goes
• vomit every now and again
• have heartburn
• keep coughing at night
• feel sick most of the time
• have diarrhoea that doesn't go away
• have times where you feel flushed, sweaty or faint

Weight loss surgery carries a risk of complications, some of which can be serious.

Before having surgery, speak to your surgeon about the possible benefits and risks of the procedure.

Blood clots

You'll have treatment to reduce your risk of blood clots after surgery, such as special leg stockings or blood-thinning medicine, but they can sometimes still occur.

Common places for clots to develop are in the lower leg (deep vein thrombosis) or lungs (pulmonary embolism).

Symptoms can include:

• your lower leg becoming painful, achy and tender
• swelling, redness or warmth in your lower leg
• a sharp, stabbing chest pain that may be worse when breathing in
• shortness of breath or a cough
• feeling faint or dizzy

Contact your GP or NHS 111 as soon as possible if you think you might have a blood clot.

Wound infection

Sometimes the wounds from your surgery can become infected while they're healing.

Signs of a wound infection can include:

• pain in or around the wound
• red, hot and swollen skin
• pus coming from the wound

Contact your GP or NHS 111 if you think your wound may be infected. They may prescribe a course of antibiotics.

Gastric band slipping out of place

If you have gastric band surgery, there's a small risk that the band could move out of position.

This can cause:

• heartburn
• feeling sick
• vomiting

See your GP if you have these symptoms and they don't go away. If your band has moved, you'll need further surgery to put it back in place or remove it.

Leak in the gut

In the days or weeks after a gastric bypass or sleeve gastrectomy, there's a small chance that food could leak out into your tummy.

This can cause a serious infection inside your tummy.

Symptoms of a leak can include:

• a fever
• a fast heartbeat
• tummy pain
• chills and shivering
• fast breathing

Call your GP or NHS 111 as soon as possible if you have these symptoms. You may need surgery to repair the leak and antibiotics to treat any infection.

Blocked gut

Sometimes the stomach or small intestine can become narrower or blocked after weight loss surgery.

This can have a number of causes, including food getting stuck, scar tissue in your gut and your gut becoming kinked or twisted.

Symptoms of a blockage can include:

• difficulty swallowing
• repeated vomiting
• tummy pain
• not needing to poo as often as usual

Contact your GP or NHS 111 as soon as possible if you have these symptoms. You may need to have a procedure to widen or clear the blockage using a thin, flexible tube passed down your throat (endoscope).

Cutting food into small chunks, chewing thoroughly and not drinking during meals can help reduce the risk of a blockage.

Malnutrition

Weight loss surgery can make it harder for your gut to absorb vitamins and minerals from food, so there's a risk you could become malnourished.

This might not always be obvious, but possible symptoms can include:

• feeling tired or lacking energy all the time
• shortness of breath
• noticeable heartbeats (palpitations)
• pale skin
• pins and needles
• feeling weak

Having a balanced diet can help reduce the risk of malnutrition, but most people need to take extra nutritional supplements for life after surgery.

You'll have regular blood tests after surgery to measure your vitamin and mineral levels, so any problems can be picked up and treated.

Gallstones

It's common to develop gallstones in the first year or two after weight loss surgery. These are small, hard stones in the gallbladder that can form if you lose weight quickly.

The main symptom of gallstones is episodes of severe tummy pain that come on suddenly and typically last a few minutes to a few hours.

In a few cases, they can also cause:

• a high temperature (fever) of 38C (100.4F) or above
• a fast heartbeat
• yellowing of the skin and eyes (jaundice)
• itchy skin
• chills or shivering
• confusion

Contact your GP if you have symptoms of gallstones. You may need an operation to remove your gallbladder.

Excess skin

As you lose weight after surgery, you may be left with excess folds and rolls of skin, particularly around your breasts, tummy, hips and limbs.

Surgery, such as a tummy tuck, can be carried out to remove the excess skin, although it's generally considered cosmetic surgery so it isn't always available on the NHS.

Ask your GP if surgery to remove excess skin after weight loss surgery is provided on the NHS where you live.

Risk of dying

Weight loss surgery is a major operation and there is a chance of dying during the procedure or as a result of a serious complication afterwards.

But this is very rare. Recent statistics suggest that only around 1 in 1,400 people who have weight loss surgery in the UK die within a month of the operation.