Bariatric Surgery

Weight loss surgery, also called bariatric surgery, is used as a last resort to treat people who are dangerously obese (carrying an abnormally excessive amount of body fat).

This type of surgery is only available on the NHS to treat people with potentially life-threatening obesity when other treatments, such as lifestyle changes, haven't worked.

Potentially life-threatening obesity is defined as:

having a body mass index (BMI) of 40 or above
having a BMI of 35 or above and having another serious health condition that could be improved if you lose weight, such as type 2 diabetes or high blood pressure

For people who meet the above criteria, weight loss surgery has proved to be effective in significantly and quickly reducing excess body fat.

The National Institute for Health and Care Excellence (NICE) is currently considering lowering the threshold for weight loss surgery to a BMI of over 30 for people who have recently been diagnosed with type 2 diabetes.

However, it is always recommended that you try to lose weight through a healthy, calorie-controlled diet and increased exercise before you consider weight loss surgery, as surgery carries a risk of complications and requires a significant change in lifestyle afterwards.

Due to these associated risks, most surgeons, whether they are working privately or for the NHS, would only consider a person for surgery if there was a clinical need, and not just for cosmetic reasons.

Who can use weight loss surgery

Weight loss surgery is only recommended for people with a BMI of 40 or more, or a BMI of 35-40 and a serious health condition that could be improved if you lose weight, such as type 2 diabetes or high blood pressure.

The National Institute for Health and Care Excellence (NICE) also recommends that weight loss surgery should only be offered on the NHS if all the following conditions apply:

You have tried all the appropriate non-surgical methods, such as diet and exercise, but have failed to achieve or maintain a beneficial level of weight loss for at least six months.
You agree to commit to long-term follow-up treatment after surgery at a specialised obesity service.
You are fit and healthy enough to withstand the anaesthetic (painkilling medication) and surgery.

Read the full NICE guidelines on treating obesity (PDF 483Kb).

There may be slightly different criteria at your local clinical commissioning group (CCG) which could affect your access to surgery.

NICE is also currently considering lowering the threshold for weight loss surgery to a BMI of over 30 for people who have recently been diagnosed with type 2 diabetes. A final decision is expected by the end of 2014.

If you pay for private surgery, it is still likely that a surgeon will only agree to perform surgery if similar criteria are met, due to the risks associated with surgery.

When weight loss surgery isn't suitable

Weight loss surgery may not be recommended if you have a serious illness that would not be improved after the operation, such as:

advanced cancer
liver disease

Weight loss surgery is also unlikely to be recommended if a mental health condition or other underlying factor means you would be unable to commit to long-term follow-up and lifestyle changes.

Examples include:

schizophrenia for which you are refusing to seek treatment
actively abusing alcohol or drugs
a previous history of not complying with medical recommendations about your care

Children

Weight loss surgery would only be considered to treat obese children in exceptional circumstances, and only if the child is physically mature (this would be around the age of 13 for girls and 15 for boys).

Most experts in obesity would only recommend surgery as a treatment of last resort for children who are severely morbidly obese (a BMI of 50 of above), or who are morbidly obese (a BMI of 40 or above) and also have a serious health condition that would improve if they lost weight.

Availability of weight loss surgery

Even if you are eligible for weight loss surgery, the demand for this surgery on the NHS is currently higher than the supply in many areas of the country. Therefore, there may be a considerable waiting list.

Weight loss surgery is also available privately. Prices are around:

£5,000-8,000 for gastric banding
£9,500-15,000 for gastric bypass surgery

An increasing number of people are seeking treatment abroad as costs for private treatment are often cheaper in other countries, but this option should be considered carefully. For more information, see planned treatment abroad.

Types of weight loss surgery

The two most widely used types of weight loss surgery are:

gastric band, where a band is used to reduce the size of the stomach so a smaller amount of food is required to make you feel full
gastric bypass, where your digestive system is re-routed past most of your stomach so you digest less food and it takes much less food to make you feel full

Several other surgical techniques may be recommended in certain circumstances.

How is it performed

Weight loss surgery and adapting to life after surgery is a challenging process, requiring the input of not just the surgeon but many different medical professionals working together as a team.

This is known as a multidisciplinary team (MDT) and it may consist of:

a surgeon
an anaesthetist
a dietitian
a psychologist
a gastroenterologist (doctor who specialises in treating digestive conditions)
a specialist weight loss surgical nurse, who will usually be your first point of contact

Most MDTs operate out of specialist bariatric surgery units, which are typically based in larger hospitals.

Before your weight loss surgery can take place, you will probably be referred to your nearest specialist unit for an assessment, to see if you are a suitable candidate for surgery.

Assessment

Your assessment may consist of three main phases:

physical assessment
psychological assessment
nutritional assessment

Physical assessment

The purpose of the physical assessment is to check whether you have any health problems or there are other factors that could complicate your surgery.

You may receive the following tests:

blood tests
an electrocardiograph (ECG), where electrodes are used to measure the electrical activity of your heart
chest X-rays
spirometer – a machine that measures how well you can breathe in and out
ultrasound scan – this uses sound waves to build up a picture of the inside of your body and is useful for spotting conditions such as gallstones and non-alcoholic fatty liver disease

Psychological assessment

The psychological assessment determines whether:

you have any mental health conditions or emotional problems that could prevent you sticking to your lifestyle plan after surgery
you have developed unhealthy patterns of eating, such as binge eating, that could cause problems after surgery
you have realistic expectations of what life will be like after surgery

The process of assessment can differ from unit to unit, but it is likely you will be asked questions about:

how obesity is affecting your emotions
how obesity is affecting your relationships with others
how obesity is affecting your daily activities
whether you are currently taking medication or seeking treatment for a mental health condition
your current pattern of eating and your willingness to change the pattern after surgery
what benefits you expect surgery to bring you and how you feel your life will be after surgery

Having a mental health condition such as depression, or an eating disorder does not automatically mean you are not suitable for surgery. However, surgery may be delayed until it is under control.

Nutritional assessment

The nutritional assessment has two main purposes.

The first is for the dietitian to obtain a detailed history of your current diet and associated patterns of eating and how these have contributed to your obesity.

The second is to ensure that you fully understand the dietary commitments you will need to make after surgery, which may include:

improving the nutritional content of your meal
eating small amounts of food slowly rather than rushing through a meal as quickly as possible

Your dietitian may also recommend that you go on a calorie-controlled diet for several weeks or months before surgery. This is because losing even a modest amount of weight before surgery is known to reduce the risks of complications, especially if you are going to have keyhole surgery.

Life after weight loss surgery

Weight loss surgery can achieve often impressive results in the amount of weight lost, but it should not be seen as a magic cure for obesity.

People who have had weight loss surgery will need to stick to a rigorous and lifelong plan afterwards to avoid putting weight back on or long-term complications.

This plan will include:

a carefully controlled diet
regular exercise

The rapid weight loss may cause relationship problems, for example with a partner who is also obese, and it may lead to unwanted loose folds of skin, which may need further surgery to correct.

Also, many people with mental health problems, such as depression or anxiety, find that these problems do not automatically improve because they have lost weight.

It is important to have realistic expectations about what life after weight loss surgery will be like.

It is very important that you stick to your recommended diet plan after your surgery.

Diet plans can differ between specialist centres and depending on your individual circumstances, but most people will be given a plan similar to the ones described below.

Diet after a gastric band operation

Your diet after a gastric band operation will progress over three main stages:

In the first four weeks after surgery, you will only be able to drink liquids and eat small amounts of pureed food, such as mashed potato.
In weeks four to six, you can you have soft food, such as chicken.
After six weeks, gradually resume a healthy diet based on eating small amounts of nutritional food.

Each stage is discussed in more detail below.

First four weeks

It is important that any food you eat during this period is pureed. Attempting to eat solid foods at this stage could put pressure on the band and damage it.

Pureed food has the same texture and consistency as baby food. You can puree food using a food processor, hand-held blender or potato masher.

Additional fluids, such as sauces or water, may be required to soften some types of food.

Aim to eat small portions four to five times a day. A portion is around 100g or five to six tablespoons of food. Eat all your meals slowly, taking small mouthfuls.

Stop eating as soon as you feel full. Due to the position of the band, you will probably experience a feeling of fullness or tightness in your chest rather than in your stomach.

Drink around 1.5 litres (2.5 pints) of water a day. Drink small glasses, around 100-200ml, between meals but never with your meals.

If you experience repeated episodes of vomiting after eating, it may be a sign that you are eating too much or that your band needs to be adjusted. Contact your surgical unit for advice.

Weeks four to six

Continue to eat a similar diet as you did for the first four weeks, but your food no longer has to be pureed, although it should be soft.

For example, you could eat:

wholewheat breakfast cereals mixed with milk
porridge
mashed potatoes and melted cheese
soup
yoghurt
rice pudding

After six weeks

After six weeks, you will be ready to adopt a long-term diet that you will need to stick to for the rest of your life. Your band should now be adjusted correctly so you should need to eat much less to satisfy your appetite.

While weight loss is an important goal of your diet, do not neglect the nutritional content of your diet. See the box, above right, for more information on what makes a healthy, nutritional diet.

The British Obesity Surgery Patient Association (BOSPA), a charity for people who could benefit from surgery, has six golden rules you will need to follow to get the maximum benefit from your gastric band:

Only eat three meals a day.
Avoid snacking between meals. If you are following your recommended guidelines, there is no reason why you should feel hungry between meals.
Eat solid food. While soft foods may be easier to digest, they usually contain more carbohydrates and fat and make you feel less full than solid foods.
Eat slowly and stop eating as soon as you feel full. Cut your food into very small chunks, around the size of a pencil-top rubber, then chew each chunk 10-25 times before swallowing. Stop eating once you feel a sensation of fullness or tightness in your chest. Overeating or eating too fast could cause unpleasant symptoms such as pain and vomiting.
Do not drink during meals. This can flush food out of your stomach pouch and make you feel less full. Avoid drinking fluids 30 minutes before a meal and for an hour afterwards.
Avoid drinking high-calorie drinks, such as cola, alcohol, sweetened fruit juices and milkshakes. These types of drink will quickly pass out of your stomach and into your small intestine, increasing your calorie intake. Ideally, drink water or zero-calorie drinks, such as diet cola or diet lemonade.

Diet after a gastric bypass

The progression of diet stages after a gastric bypass is broadly similar to those after a gastric band:

In the first week after surgery, drink liquids only (this does not include pureed food).
In weeks two to four, you can eat pureed food in the same quantities (100g) and frequencies (four to five times a day) as described above.
In weeks four to six, you can eat soft food.
After six weeks, gradually resume eating a healthy diet.

The golden rules above also apply to your diet after a gastric bypass.

However, you need to be aware of several additional issues.

Firstly, you will need to avoid eating food that is high in sugar, such as chocolate, cakes, sweets and biscuits. This is because your bypass will affect how you digest sugar, and any sugar you eat will trigger your body to produce high levels of insulin.

The excessive amount of insulin can cause a number of unpleasant symptoms that are collectively known as dumping syndrome. Symptoms of dumping syndrome include:

nausea
abdominal (tummy) pain
diarrhoea
light-headiness

Secondly, you will need to take daily vitamin and mineral supplements, as your small intestine will no longer be able to digest all the vitamins and minerals your body needs from your diet.

The dosage and type of supplements can vary from case to case, but most people are required to take:

a multivitamin supplement, which contains a combination of different vitamins
a calcium supplement (the body requires calcium to maintain healthy bones)
an iron supplement

Diet after other types of weight loss surgery

The recommended diet after other types of weight loss surgery is likely to be similar to the advice above.

Your specialist centre will be able to provide more detailed advice.

Exercise after weight loss surgery

Losing weight and then maintaining a healthy weight does not simply involve reducing the amount of calories you eat. Burning calories while exercising is also important.

Regular exercise also has additional health benefits other than weight loss. These include reducing your risk of developing heart disease and some types of cancer, and boosting your self-esteem and wellbeing.

You will probably be given an exercise plan that starts gradually with low to moderate amounts of physical exercise, such as 10 minutes a day, before the amount is gradually increased.

The exercise should be intense enough to leave you feeling out of breath and getting your heart beating faster.

Recommended types of physical exercise include:

activities that can be incorporated into everyday life, such as brisk walking, gardening or cycling
supervised exercise programmes
activities such as swimming, walking (where you aim to walk a certain number of steps a day) and stair climbing

Chose physical activities that you enjoy as you will be more likely to continue doing them.

Further information

Read more about fitness including information on:

Risks

As with all types of surgery, weight loss surgery carries the risk of complications, some of which are serious and potentially fatal, such as:

internal bleeding
a blood clot inside the leg (deep vein thrombosis)
a blood clot or other blockage inside the lungs (pulmonary embolism)

A 2014 American review of over 157,000 patients found the overall risk of death, within 30 days of having any kind of weight loss surgery, is around 1 in 1000. The risk of death after having a gastric bypass was slightly higher.

However, certain risk factors, such as high blood pressure or a BMI of 50 or above, increase the risk of complications.

Results

As long as a person is willing and able to stick to their agreed plan afterwards, surgery can effectively reduce their weight and treat conditions associated with obesity, such as diabetes.

Recent research carried out in America found that on average:

people with a gastric band will lose around half their excess body weight
people with a gastric bypass will lose around two-thirds of their excess body weight

Both techniques also lead to a considerable improvement (and sometimes a complete cure) of obesity-related conditions, such as diabetes or high blood pressure.