Gastric Bypass Clinics (Roux-en-Y)

Private Gastric Bypass Surgery in the UK

Your Gastric Bypass with Allure

The gastric bypass (otherwise known as the roux-en-y gastric bypass) is a tried and trusted form of weight loss surgery that has seen success for decades. Utilised globally for its drastic impact when it comes to tackling obesity and comorbidities associated with weight, Allure Weightloss is proud to offer the gastric bypass to our private weight loss patients across the United Kingdom.

As a CQC registered provider, you can trust in our dedication to high quality patient care throughout. All Allure Weightloss Patients are privy to specialist aftercare appropriate for the weight loss procedure that they are electing for.

A gastric bypass is not to be mistaken for a gastric sleeve. Unlike the sleeve, the gastric bypass does not involve the removal of any of the stomach tissue. Instead, our GMC registered consultant surgeon will create a new structure out of the existing stomach. This new structure, commonly referred to as a ‘pouch’, drastically limits the amount of food you can consume at any one time, limiting calorie intake and thus inducing weight loss. Over a two-year period you can expect to lose up to 70%of your excess weight.

The gastric bypass is a permanent procedure, and anyone looking to undergo surgery should take their time to carefully consider all their options. This is why our team provide you with all the necessary information to make a measured and informed decision. If you need more help and guidance or would like to begin your weight loss journey with us, you should speak to one of our patient advisors today.

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.

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



Am I Eligible for the Gastric Bypass?:

  • 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.

Your consultant 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 Can Allure Patients Expect?

One of your first questions might be around who will be involved in your gastric bypass journey. You should expect to be in contact with our specialist consultant surgeon, dietitian, and nurse. On the day there will also be an anaesthetist who will ensure that your surgery is as comfortable as possible for you.


Naturally, you will be assessed to check whether you are eligible for the operation. This may include blood tests, x-rays, and scans, as well as an explanation of the surgery and long-term outlook. What is involved in your pre-operative assessment/s will all depend on your medical history.

You may need to lose some weight before the surgery itself. You may also be required to reduce the size of your liver. This is to make the operation safer as your liver will be smaller and there will be more room to access the stomach itself.

Avoid eating for several hours before your gastric bypass. You may continue to drink clear liquids until two hours prior. You may need to stop medication in preparation for your bypass surgery and our consultant will advise you of this.

During Your Surgery

As a major operation the gastric bypass is carried out under general anaesthetic. The surgery is usually completed laparoscopically (keyhole), though this method isn’t suitable for everyone.

During the operation, your consultant surgeon will make small incisions in your abdomen to pass through a tiny camera and instruments. They will then inflate your abdomen with carbon dioxide gas. Next, they will use surgical staples to make a pouch, about the size of a walnut, at the top of your stomach and trim your small intestine and attach the lower part of it directly on to your new pouch. They will then join the remainder of your stomach and upper small intestine to the lower part – this is so digestive juices from your stomach can drain out. Finally, the consultant surgeon will then close the incisions.

Recovery Expectations

After six weeks you should be back to normal activities. By this time you will have followed (and will continued to follow) a controlled diet as instructed by our dietitian. As a result of rapid weight loss, you are likely to experience several symptoms: aches, tiredness, dry skin, feeling cold, thinning hair, and fluctuations in mood. After three to six months you should be experiencing less of these symptoms.

Aftercare / Ongoing Treatment

Your recovery care will include pain relief, a review of your medications, a carefully established diet, and an exercise plan. You will also be provided discharge medication that may include Vitamin D, Calcium, multivitamin A-Z with iron, Vitamin B12, and Lansoprazole. You will also have several follow-up appointments.

Post-Op Lifestyle

Your life will be a little different after you’ve had a gastric bypass. We touch on a few of these below.

Please note that the surgery will not stop you craving or prevent you from eating unhealthy foods. You will be required to make the necessary long-term changes that the surgery is designed to facilitate.

You will need to wear compression stockings for the first two weeks. This is to prevent blood clots forming. Furthermore, please do not take a bath for one week. You may still shower, but please ensure 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 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).

Potential Side Effects

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.

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. 

Spire Bushey Bariatric Surgery and Orbera 12 Month Gastric Balloon Clinic


Heathbourne Road, Bushey
WD23 1RD

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


Uttoxeter New Road
Derby, DE22 3NE

bariatric surgery in manchester, oaklands hospital


19 Lancaster Rd
Salford, M6 8AQ

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. We do not advise drinking alcohol.

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.
Can I Smoke?
  • You must quit smoking at least 6 weeks before surgery. You must also not smoke at all after the surgery. Smoking can increase  your chance of complications, such as stricture. 

Enquire Today

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.