Gastric Bypass Surgery

What Is Gastric Bypass Surgery?

Gastric bypass surgery is a weight loss surgery that can usually be performed in a keyhole (laparoscopic) procedure, unless the patient is severely obese. The procedure essentially shortcuts the normal procession from stomach to the rest of your digestive system, reducing the space available for your to take in food, making you feel fuller quicker. Gastric bypass procedures usually results in a greater, faster weight loss than gastric band operations, however the procedure is far more permanent, so all options should be considered before opting for this procedure.

Can I Have Gastric Bypass Surgery?

To qualify for getting surgery on the NHS, you must fulfil their specific eligibility criteria, which are similar for all weight loss surgeries; you will be eligible if:

  • You have a BMI of at least 40, or;
  • You have a BMI of at least 30 and are suffering from a condition that would benefit from weight loss, such as type 2 diabetes In a private setting, whether you are eligible varies from practice to practice, however they often use similar criteria to those above with the extra criteria of not being able to lose the weight through conventional methods such as exercise and/or healthy diet alone.

A number of alternatives should be tried before opting for surgery, and any gastric surgical procedures are considered to be the last resort. Patients should have tried dieting and exercise first – if these methods are unsuccessful your GP will then want to discuss more complex methods for weight loss. As with all surgery, you should always consult your GP to discuss your options and be fully aware of all procedures before making a choice.

Private Gastric Bypass Surgery

Many patients opt to undergo their weight loss surgery privately, to speed up the waiting time or if they do not qualify for an NHS procedure. The cost of bypass surgery varies between private providers, but is typically much more expensive than a banding procedure, costing from £9000-15000. It is vital that you choose a quality private practice, as the promise of cheap gastric bypass surgery can often lead to medical mistakes or unnecessary complications.

What Next?

We'll help you find affordable weight loss clinics

Compare Quotes

The Procedure

The surgeon will make a small incision into your abdomen to allow insertion of a small instrument called a laparoscope, which is essentially a camera and light attached to a long rigid tube that relays footage to a nearby screen. By inserting a laparoscope, the surgeon is able to perform the procedure through a small incision drastically reducing the risk involved.

Before gastric bypass surgery

Other small surgical instruments are then inserted through further small incisions in the patient's abdomen and a small pouch in created from your stomach, dramatically reducing its size. This small pouch is then directly connected to the small intestine, effectively bypassing the rest of your stomach and allowing food to travel from the pouch through the new route to the small intestine.

After gastric bypass surgery

Your Diet Before Surgery

In the time leading up to your gastric band procedure, your doctor will recommend a healthy eating and exercise plan, in order to ensure you are in the best health possible for your procedure.

A liquid diet is introduced two weeks before the operation where both protein shakes and clear liquids are regularly consumed. Around four protein shakes are taken daily, each containing at least 20 grams of protein and less than 150 calories. The clear liquid is important for keeping the body hydrated and shrinking the liver as it sits just above the stomach and must be lifted during the surgery. Multivitamins are also required during this period and women need to take calcium supplements.

Your Diet After The Surgery

Watch Mr Chris Sutton, Consultant Specialist Bariatric Surgeon at Tonic Weight Loss Surgery Ltd, describe the recommended diet following a gastric bypass procedure:


Video Transcript

"In terms of lifestyle changes people are on a liquid diet for two to three weeks following surgery then they are on a soft diet for the next two to three weeks, and then they’re on normal textured food. That allows time for both the band to form a capsule around it so movement will be minimal and for the sleeve and the bypass to heal fully."

Mr Chris Sutton, Consultant Specialist Bariatric Surgeon at Tonic Weight Loss Surgery Ltd


Your diet following gastric bypass surgery will be explained in detail to you by your medical team, but it is likely to proceed in four stages:

  • In the first week after surgery you will only be allowed to drink liquids such as sugar-free juice and clear broth. This does not include pureed food and fizzy drinks are out of bounds.
  • For the following two-three weeks you will be allowed to eat pureed food, normally set at 100g portions four to five times per day.
  • In weeks four to six, you will be allowed to begin eating soft foods such as scrambled eggs, low-fat cottage cheese and blended lean cuts of meat or fish. It is very important that meats are blended well and are extremely soft and smooth in texture.
  • After six weeks, you can gradually resume eating a healthy diet based around taking in small amounts of nutritional food.

Any snack or meal consumed should be small in size. Liquids should also be consumed between meals. It is recommended to eat 3-6 small meals per day, and never over eat.

This period will be directed by your physician who will monitor how your stomach reacts and adjust your diet accordingly.

There are numerous lifestyle changes that occur following a gastric bypass; you will be required to stick to a low-fat, low-calories, small-portion diet for the rest of your life, as well as taking nutritional supplements.


If the surgery went smoothly, you should be able to resume your everyday activities within two weeks, although you may still be in a small amount of pain. "Everyday activities" include bathing, gentle walking and household tasks. It does not include vigorous exercise or heavy lifting. You should ensure you are fully healed before exerting yourself too much.

Although you may be in pain, it is important that you partake in gentle exercise every day. This will not only help your body to heal, but it also helps with weight loss. Your hospital should give you a list of some easy exercises you can do at home. This is likely consist of light stretching and short, slow walks.

What Next?

We'll help you find affordable weight loss clinics

Compare Quotes

Risks and Complications

As with any surgery, gastric bypass procedures come with a number of potential complications, including immediate complications such as:

  • Infection.
  • Internal bleeding.
  • Blood clots in the legs (deep vein thromboses).
  • Blockages in the lungs (pulmonary embolism).

Gastric bypass surgery also has a number of longer term risks, which may occur some time after surgery, including:

  • Excess skin.
  • Food intolerance.
  • Gallstones.
  • Blockage of the hole that connects the stomach pouch to the small intestine (stomal stenosis).

Life After Gastric Bypass Surgery

Life after surgery is, in the main, reported to be much healthier with patients getting back their self esteem and confidence lost behind baggy clothes and excuses. Patients feel healthier due to a change in diet and some even report an increase in friends, job opportunities and feelings of being attractive.

Many patients have also reported that they have had to cut down on clothes shopping because they lost weight so rapidly that, before long, new clothes no longer fitted them. Others reported a reduction of asthmatic attacks and some even report that they have stopped taking their asthmatic medication completely. On average, patients lose 100 pounds of weight and enjoy a life free from many obesity related medications such as those for diabetes, high blood pressure and sleep apnea.

Considering Surgery?

Weight loss surgery does not give immediate results and only works as part of a regime which you must follow strictly in order to lose weight. It should only be viewed as a last resort and should not be attempted before trying other methods of weight loss, such as changing diet and increasing exercise. If you are considering stomach bypass surgery, you should consult your GP as soon as possible to discuss your options.

What Next?

We'll help you find affordable clinics

Compare Quotes