Ask a Surgeon: Gastric Bypass Q&A with Mr Naga Jayanthi


In this blog post, consultant surgeon Mr Naga Venkatesh Jayanthi answers the most common questions regarding gastric bypass.

Q1. How overweight do I need to be to qualify for gastric bypass?


Eligibility for a gastric bypass depends on your Body Mass Index (BMI). This is calculated by dividing your weight (in kilograms) by your height (in metres) squared.

According to NICE guidelines, you are eligible for a gastric bypass if you have a BMI of more than 40 or if your BMI is more than 35 with any obesity related health conditions (such as diabetes, high blood pressure, knee / back pain, sub-fertility or infertility, sleep apnoea, depression and so on).

Q2. How much weight will I lose after gastric bypass surgery?

Weight loss after any bariatric surgery is calculated as a proportion of your excess body weight.

Following gastric bypass, patients loose on an average of 60 - 70% of their excess body weight. However, the amount of weight lost by each patient will vary depending on individual circumstances.

Q3. Should I have keyhole surgery or open surgery?

Keyhole surgery is very preferable to open surgery. In fact the vast majority of the gastric bypass operations in the UK are performed via keyhole surgery.

Q4. How long does a keyhole gastric bypass surgery take? How long is the hospital stay after?

On average, keyhole gastric bypass can take from 1 ½ to 2 hrs. Patients are expected to be very mobile after the operation and independently mobile the day after surgery.

The usual hospital stay is for two nights but there are some centres where suitable patients are discharged home on the first day after the operation.

Q5. How big will my stomach pouch be after surgery?


Exact stomach pouch size varies with each surgeon / surgical technique. On average it can be between 30ml to 50ml. Nevertheless, it is ensured that the pouch is very small and you are able to eat only small portions after the surgery.

Q6. How long is the expected recovery from a gastric bypass? How much time off work should I get?

As mentioned above, you are expected to move around independently by the first day after the operation. The time you need to be off work depends on what kind of work you do and your general health before the operation. Therefore this can be very variable. It is best to discuss this with your surgeon.

Q7. What are the common symptoms after gastric bypass surgery?

Nausea and pain tend to be the commonest symptom after gastric bypass. Your surgeon will give you anti-sickness medications along with painkillers when you are discharged from the hospital. All these medications should be either in soluble or liquid form. You will also be discharged on anti-clot stockings and an injection for thinning your blood.

Q8. Am I eligible for gastric bypass if I have a gastric band?

Absolutely. You can have a gastric bypass, if the gastric band isn’t working, if it's slipped or if you're not loosing weight. There are increased risks because of scar tissue from band surgery but your surgeon will be able to explain this in detail.

Q9. Is child birth after gastric bypass ok?


Gastric bypass improves fertility in obese females and thus increases chances of pregnancy. However, you should avoid falling pregnant in the first year after gastric bypass.

Q10. Will a gastric bypass help with my back pain?

If the back pain is obesity related, gastric bypass surgery will improve your back pain.

Q11. Will a gastric bypass help with my diabetes?


Gastric bypass is the most effective weight loss operations for patients with diabetes. Diabetes fully resolves or significantly improves (decreased dosage of diabetic medication – insulin & tablets).

Q12. How long after gastric bypass surgery can I fly?

The main risk of flying after gastric bypass is the chance of developing clots in the legs (DVT – Deep Vein Thrombosis), which may then travel up to the lungs (PE – Pulmonary Embolism).

In general, it is advisable not to fly long distances up to about four – six weeks after gastric bypass. Even after this, you should take all precautions to decrease the chance of the above by wearing anti-clot stockings, drinking plenty of water and also walking in the plane every 2 hours.

Furthermore, you need to take the postoperative dietary requirements into consideration if you are going on holiday.

Here you can find our guide prices for bariatric surgery.

Read more weight loss surgery blog posts to find answers to the most common questions including: pros and cons of gastric balloon and gastric sleeve, how to choose a weight loss surgeon, exercise after weight loss surgery etc.

About Mr Jayanthi

Mr Jayanthi is a laparoscopic gastro-intestinal surgeon specialising in Weight Loss Surgery and in the treatment of diseases of the oesophagus & stomach at Springfield Hospital in Chelmsford, Essex.

He has been presented a number of medical awards such as the prestigious David Dunn Travelling Scholarship, where he travelled to Japan and India to visit some of the leading surgeons in the world and has learnt a number of innovative techniques, which he practices while treating patients in the UK.

Read more about Mr Jayanthi qualification, background and clinical interests

About Ramsay Health Care UK Weight Loss Surgery

Ramsay Health Care is a leading provider of weight loss surgery in the UK. Ramsay Health Care is a leading provider of weight loss surgery in the UK.

Ramsay offers weight loss procedures including gastric banding, gastric sleeve, gastric bypass and gastric balloon.

Ramsay works in partnership with some of the highest qualified and experienced weight loss surgeons in the UK. These consultant bariatric surgeons will discuss the benefits and risks of weight loss surgery with all patients before they make a decision to go ahead with the surgery.

The consultant bariatric surgeons have undergone intensive training in weight loss surgery and they will ensure you receive the best treatment for your individual needs.

Please contact us if you would like to discuss gastric bypass surgery in more detail.

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