Gastric Bypass Clinics (Roux-en-Y)

Private Gastric Bypass Surgery

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The Health Benefits of Gastric Bypass Surgery
  • Weight Loss Expectations: Patients can lose up to 70% of their excess weight in the two years post-op.
  • Improve Comorbidities: weight-related conditions that you might have such as type 2 diabetes, heart disease, osteoarthritis, obstructive sleep apnoea, high cholesterol, and polycystic ovaries
  • Physical Activity: Patients find they are more able to do physical activity than they were beforehand.
An Overview:


Length of Stay

1-2 nights

Procedure Duration

1-4 Hours



What is the Gastric Bypass?

A Roux-en-Y Gastric Bypass is a weight loss surgery aimed at reducing the risks of weight-related conditions (comorbidities). The way it works is by creating a structure that drastically reduces the space inside your stomach, leaving you feeling full for longer. This involves creating a small upper pouch of the stomach which is directly connected to the intestines. This is a permanent procedure, and you will need to make the appropriate lifestyle changes in response to it. 

This causes the following:

  • Restriction – you won’t be able to eat as much as before.
  • Malabsorption – you’ll absorb fewer calories because your food will come into contact with less of your small intestine.
  • Deterrent – you won’t feel like eating a lot of sugar because if you do, your body will produce too much insulin, making you feel light-headed and sick. This is called ‘dumping syndrome’.

Your surgery will last up to around 4 hours, and you should expect to stay for one night (minimum) in the clinic. You should also plan to have 2 – 3 weeks off of work and expect a full recovery between 6 – 8 weeks. 

The average weight loss experienced by patients who have a gastric bypass is up to 70% of their excess weight. 

Our private surgeries take place in Manchester, Derby, and North London. Speak with a specialist for more information. 

A Doctor may Recommend the Roux-en-Y Gastric Bypass If:

  • You have a BMI of 35.
  • You’ve already attempted to lose weight via traditional methods such as dieting and lifestyle changes. 
  • You’re willing to have long-term follow-up appointments.
  • You are willing to adopt a healthy diet and lifestyle.
  • You’re medically fit for surgery and anaesthesia.

The Doctor may recommend gastric sleeve surgery first.

Gastric bypass surgery is not recommended for children and young people.

You may be required to pass a psychological assessment first.

Potential alternatives to gastric bypass surgery include:

What Gastric Bypass Patients can Expect

Who will be Involved?

  • Specialist Consultant Bariatric Surgeon
  • Our Specialist Dietitian, Chris
  • Our Specialist Bariatric Nurse, Jodi
  • Anaesthetist

Pre Op

You’ll be assessed to check that you’re fit for the operation. This may include blood tests, x-rays, and scans, as well as an explanation of the surgery and long-term outlook. You may need to lose weight and reduce the size of your liver. If your liver is smaller, the operation will be easier and safer.

You shouldn’t eat for several hours before your gastric bypass, but you can continue to drink clear liquids until two hours before. Should you need to stop any medication in preparation for your bypass surgery, your doctor will tell you. You’ll also have plenty of time to ask any questions and discuss your concerns before your surgery.

During Gastric Bypass Surgery

A gastric bypass is a major operation so it’s carried out under a general anaesthetic.

It’s usually done by laparoscopic (keyhole) surgery, though this method isn’t suitable for everyone. 

During the operation, your surgeon will:

  • Make small incisions in your abdomen and pass through a tiny camera and instruments 
  • Inflate your abdomen with carbon dioxide gas
  • Use surgical staples to make a pouch, about the size of a walnut, at the top of your stomach
  • Trim your small intestine and attach the lower part of it directly on to your new pouch
  • Join the remainder of your stomach and upper small intestine to the lower part – so digestive juices from your stomach can drain out
  • Close your incisions

If your surgeon thinks keyhole surgery isn’t suitable for you, they may suggest open surgery, which involves making one single, much larger incision.

Pain After Gastric Bypass Surgery

It’s normal to feel some pain and discomfort after gastric bypass surgery. It is important to remember that it’s different for everyone. You will be provided with pain relief.

Hospital Stay

You’ll usually be in hospital between one to two nights. After your surgery, you’ll be given compression stockings or blood-thinning medication to reduce your risk of blood clots, which can lead to complications such as deep vein thrombosis.

Recovery Expectations

Recovery Timeline

You should be back to your normal activities after six weeks. You will have followed and continue to follow a controlled diet, but may experience changes as your body reacts to rapid weight loss. This includes symptoms such as:

  • Aches
  • Tiredness
  • Dry skin
  • Feeling cold
  • Thinning hair
  • Fluctuations in mood

After three to six months you should be experiencing less of these symptoms.

Aftercare and ongoing treatment

Your recovery care will include:

  • Pain relief
  • A review of any medicines you’re taking for weight-related conditions, such as diabetes or high blood pressure
  • A carefully controlled diet plan for the first four to six weeks, moving from liquids to pureed, soft then solid foods, plus advice on eating and portion sizes
  • An exercise plan to help speed your weight loss and improve your fitness
  • Discharge medication – which can include vitamin D, calcium, multivitamin A-Z with iron, vitamin B12, Lansoprazole
  • Follow-up appointments

Post-Op Lifestyle

The surgery won’t stop you craving or eating unhealthy food, so you must be willing to make long-term lifestyle changes.

You’ll need to wear compression stockings for the two weeks after your surgery to prevent blood clot formation.

You can shower, but must not bathe for a week. You must ensure that all dressings are kept clean and dry.

You’ll need to attend follow-up appointments for the rest of your life. Eventually, these may just be annual checks to make sure your bypass is working properly. You’ll also need to have have blood tests at regular intervals for the first two years after your surgery.

You can expect to return to work between two to four weeks after your surgery, though this depends on the type of job that you do. You’ll have to request a fit note from your ward doctor, should you need one. You can usually drive within two weeks of your surgery, but you should check with your doctor and your policy first.

You should keep active after your operation to reduce the risk of blood clots forming, however, you should try to avoid any abdominal or heavy exercises for at least six weeks.

As you start to lose weight after your bypass surgery, your body will need more protein to maintain your muscle mass and have a healthy metabolism. You’ll need to increase the amount of protein in your diet otherwise your body will start to rely on the protein from your muscles which will weaken them.

Avoid drinking at the same time as eating to prevent vomiting and dumping syndrome. This is an uncomfortable set of symptoms caused by the food in your stomach being too sugary, or quickly washed into the small intestine through the join. Ensure that you’re drinking plenty of water throughout the day to prevent constipation.

If you’re planning to travel by plane within a few months of surgery, you should speak to your doctor first. Some complications may occur including deep vein thrombosis (DVT).

You can continue to have sex when you’re ready but you should avoid becoming pregnant during the first 12 to 18 months after surgery. Your nutritional levels are likely to be low during this time, which could harm your baby.

Potential Side Effects of the Gastric Bypass

Due to weight loss, you may find that you start to lose some hair, or it becomes thinner. Although this can be distressing, it is only temporary, usually improving in the first few months. 

Your skin may also become very dry after your gastric bypass surgery. This can be improved this by drinking plenty of fluids, taking your multivitamins and applying a good moisturiser. 

As your body reacts to rapid weight loss in the first three to six months, you can also experience body aches, tiredness, flu-like symptoms, feeling cold and fluctuations in mood.

Gastric Bypass Results

The amount of weight you lose depends on your change in lifestyle habits, though you can expect to lose up to 90% of your excess weight within one year of surgery. As well as your weight loss, you may find that your gastric bypass surgery will improve other conditions related to being overweight including heart disease, high blood pressure and joint pain.

Did You Know?

The gastric bypass was initially developed in the 1960s, after two doctors observed the weight loss experienced by patients undergoing partial stomach removal for ulcers. Over several decades the technique as we know it today, the Roux-en-Y Bypass, was developed.

GMC Registered Bariatric Consultant Surgeons

We only work with the highest-level bariatric consultant surgeons who perform the gastric bypass. They are all leaders in their field. Learn more about our bariatric consultant surgeons by clicking on their images.

Mr Javed Sultan, consultant bariatric surgeon
Mr Javed Sultan, Manchester
Mr Periyathambi Jambulingam
Mr Periyathambi Jambulingam, London
Allure Consultant Mr Brij Madhok
Mr Brij Madhok, Derby

Private Gastric Bypass Clinics

Our gastric bypass clinics were selected for the existing high-standards of said facilities and the ability to meet the standard of patient care demands that we would expect. You can learn more about our gastric bypass clinics by clicking on the images below. 

bariatric surgery in manchester, oaklands hospital


Oaklands Private Hospital, 12 Lancaster Road, Salford, M6 8AQ
Bypass, Sleeve

Spire Bushey Bariatric Surgery and Orbera 12 Month Gastric Balloon Clinic


Heathbourne Road, Bushey
WD23 1RD
Weight Loss Surgery & Orbera Clinic

Entrance to Derby private health clinic. Light green wall, sign, and two plants.


Uttoxeter New Road
Derby, DE22 3NE
Bypass, Sleeve

Associated Risks

As with any surgeries, there are risks involved in the gastric bypass procedure. These include excessive bleeding, infection, and blood clots among others. During your initial consultation, the Bariatric Consultant will be able to talk through these risks with you, including any questions you may have about them.

Gastric Balloon Consultants Crossing Arms
Zoom call consultation with a Allure Weightloss Doctor

Gastric Bypass Aftercare

Don’t worry, you won’t be left to your own devices after surgery. You will be privy to 2 years of Aftercare from Allure Weightloss Specialists. This includes regular contact with a Bariatric Nurse and HCPC Registered Dietitian as standard. This is to help encourage those essential and necessary lifestyle changes to ensure the gastric bypass works as intended.

Calculate Your BMI

In order to have a gastric bypass you need a BMI of at least 40. If you have a BMI of 35 you may be eligible, depending on whether you have any co-existing medical conditions or concerns. You can use our Calculator in order to determine your BMI, or use the NHS BMI Calculator.

How is body mass index (BMI) measured? 

An individuals BMI is calculated by using the following formula: 

BMI = Weight (kg) / Height (m)²

You must take your weight in kilograms, divide it by your height in meters, and then divide it a second time by your height in order to determine the correct body mass index. 

Not sure you qualify?

If you still aren’t sure, a member of our team will be able to help. If you are certain you won’t qualify for gastric bypass surgery, you still may be eligible for other medical weight loss treatments. 

BMI Calculator
Use this Calculator to Check Your Body Mass Index (BMI).
Please enter a value between 125 and 225.
Please enter a value between 10.0 and 500.0 ( one decimal )
Calculate BMI
Use this calculator to check your body mass index (BMI), which can be useful in determining your eligibility for treatment.

Frequently Asked Questions

Weight Loss Expectations

  • Most patients can expect to lose up to 70% of their excess weight in the 18 months after their surgery.

What is Dumping Syndrome?

  • Dumping syndrome is a collection of uncomfortable symptoms, such as feeling sick, weak, faint, sweaty and diarrhoea, caused when sugary foods move from your stomach into the small intestine too quickly.
  • Avoid drinking and eating at the same time to help prevent dumping syndrome.

What can I eat After Gastric Bypass Surgery?

  • After surgery, you’ll not be able to eat until your X-ray and swallow test. At first, you’ll have to eat a soft diet and your dietitian will give you a diet plan for the weeks after surgery.

Can I Have Excess Skin Removed?

  • Surgery can be used to remove this excess skin, although under normal circumstances this is considered to be a cosmetic procedure.

What Qualifies Me for Gastric Bypass Surgery?

  • Must have a body mass index (BMI) of 35.
  • You must have also tried to lose weight through diet and lifestyle, and be willing to have long-term follow-up appointments and adopt a healthy diet and lifestyle. You’ll also need to be medically fit for surgery and anaesthetic.

How Dangerous is Gastric Bypass Surgery?

  • Gastric bypass surgery is a common procedure and most people have it without complications, but all surgery carries some risks. Your consultant will discuss potential risks and complications with you before the operation.

Can I Regain Weight?

  • Yes. The surgery won’t stop you craving or eating unhealthy food. You must be willing to make long-term lifestyle changes in order to avoid putting weight back on.

How Long do I Need off Work?

  • Depending on how strenuous your work is, you may need to recover for two to four weeks before returning to your job.

Is the Gastric Bypass Permanent?

  • Gastric bypass surgery is generally non-reversible. There is a risk of you reversing your weight loss if you do not follow the advice provided.

Can I Drink Alcohol?

  • It’s not recommended that you drink alcohol for the first six months. You will feel the effects of the alcohol faster than before. This is because you will absorb it differently.

Can I Drink Caffeinated Drinks?

  • It’s okay to drink caffeine after your gastric bypass surgery, but you should avoid drinking too much as it acts as a diuretic and can cause dehydration.

What Medications Should I Avoid?

  • You should avoid taking a class of medication known as non-steroidal anti-inflammatory drugs (NSAIDs) as these can irritate your stomach and cause stomach ulcers. Common drugs in this category include aspirin, ibuprofen, and naproxen.

How Much Water Can I Drink?

  • You should try to stay hydrated throughout the day after your gastric bypass surgery. Your dietitian will advise you on what you should be drinking in detail. Please avoid fizzy and sugary drinks.

What Happens if I Don’t get Enough Protein?

  • As you start to lose weight after your bypass surgery, your body will need more protein to maintain your muscle mass and have a healthy metabolism. If you don’t get enough, your body will start to rely on the protein from your muscles. This will cause them to weaken.

Can Gastric Bypass Surgery Cause Low Iron?

  • Yes. After your surgery, your stomach may start to digest things differently, including the iron in your foods. You may need to take iron supplements during your recovery to prevent any deficiencies, your doctor will advise you.35

Ask About Gastric Bypass Consultations, Cost, and More

Start the process and book your private gastric bypass consultation today with Allure Weightloss. Simply speak to a member of our team to discuss the procedure and pathway in more depth. Allure Weightloss is a CQC registered provider of bariatric surgery in England and Wales.