Gastric Bypass

To find out more about this procedure follow the links below to our partner Phoenix Health

The gastric bypass is the most highly regarded procedure for treating severe obesity. 30 years of refinement means that it is now a highly effective, reliable operation with the risk of serious side effects reduced to a minimum.

The procedure involves using keyhole surgery and specially designed equipment to change the way food is passed through the intestines. Firstly, the stomach is reduced to a small pouch similar in size to a large egg. The small intestine is then carefully transected and reattached to the resized stomach pouch. The reduced volume of the stomach means only a much smaller amount of food can be consumed which then bypasses the first metre or so of the small intestine. This change causes the body to release large amounts of naturally occurring hormones that suppress appetite and improve the body’s control of blood sugar levels. A gastric bypass only has a small effect on the absorption of food and so patients rarely suffer from the side effects of malabsorption such as diarrhoea or other severe nutritional problems.
Overall the gastric bypass is more forgiving than the gastric band and is easier to live with longer term.

The gastric bypass is highly regarded because of the results that can be achieved in terms of sustained weight loss and resolution of diabetes. Typically, 70-80% or excess weight can be lost within two years and many patients who undergo the procedure with type 2 diabetes see a significant improvement in the control of blood sugar levels, often without needing any regular diabetic medication. These results have a huge impact of patient’s lives, both in terms of reduced illness and comorbidity, and also the positive effect on their physical and psychological well-being.

Follow-up care is vital and any persistent vomiting or excessive weight loss should be investigated promptly. Regular blood tests are also carried out every three to four months and should include trace elements such as iron, zinc and magnesium as well as vitamin B12 and folate levels. Many bariatric patients suffer from depleted/deficient vitamin D even before their surgery so we routinely supplement this too.

A common issue in the first few months following the procedure is a stricture (narrowing) of the new opening between the stomach and the small intestine. This is easily treatable, by stretching the area with a small balloon that is passed down a gastroscope – a small camera that is used to examine the stomach under sedation. Other complications are similar to those of the sleeve gastrectomy, and include staple line leakage, bleeding and injury to adjacent internal structures. Ensuring the operation is performed by experienced surgeons with a good multi-disciplinary team will minimise the risk of these complications. Further problems are rare, however patients and clinicians should be aware of an increase in the risk of gallstones following rapid weight loss and unusual abdominal pain (but not accompanied by vomiting), which can indicate the presence of an internal (Petersen’s) bowel hernia.

One notable side effect that is worthy of a mention is Dumping Syndrome. This results from the rapid emptying and absorption of sugars in the small bowel which causes an over exaggerated insulin response. Blood sugar levels quickly fall and the patient experiences symptoms of hypoglycaemia (low blood sugar) which can include anxiety, sweating, dizziness and fainting. Stomach cramps and diarrhoea often precede it, bringing about a useful degree of caution in the chocolate-loving bariatric patient.

Enhanced Care Programmes Silver Gold Platinum
Treatment of complications – 3 months ­ ­ ­
Follow up and Band Fills – 2 years ­ ­ ­
Education Programme – 2 years ­ ­ ­
Surgeon Led Follow Ups ­ ­ ­
Bariatric Gift Box ­ ­ ­
Up to 8 individual consultations with psychologist ­ ­ ­
Up to 16 individual consultations with psychologist ­ ­ ­
  • Arranging your Treatment

    Before going ahead with this treatment, you will need to have an initial consultation with a specialist Consultant to go through your medical history and diagnosis. At this appointment, your consultant will confirm the exact treatment you require.

    If you would like to have an initial consultation, you can call us and we can help you find the consultant best for you.

    Alternatively, if you have already been diagnosed as needing a particular operation or treatment, our Reservations team can give you a guide price for this to be carried out at KIMS Hospital and book an appointment for you to meet a consultant.

    Call our Reservations team on +44 (0) 1622 237 727 or email

  • Paying for your Treatment

    You can be treated at KIMS by using your private medical insurance or by paying for yourself.

    If you have private medical insurance, you will need to contact your insurer to ensure you are covered for the initial consultation prior to making an appointment and obtain an authorisation number. The insurance company will then need to be advised if you require further treatment. The insurance company usually settles bills on your behalf.

    If you are paying for your own treatment, you will need to pay for an initial consultation.  This will be confirmed at the time of booking but is typically £150-£250. You will also need to pay for any associated diagnostic tests your consultant recommends (for example x-rays and blood tests).

    Following this consultation, if you don’t need any further treatment or if you decide paying for yourself isn’t the right option, there is no commitment to proceed further.

    If you require the operation or procedure to be carried out, you will receive a quote for your treatment. In most case this will be the fixed price package quoted on this website. If this quote is different for any reason, we will provide an explanation (see what’s included below). This quote is also subject to pre-assessment checks prior to your admission to hospital.

    Payment is required 7 days prior to admission.

  • What’s Included

    The fixed price package above includes all the costs associated with this treatment at KIMS Hospital.

    You will be given a quote prior to admission to confirm this cost. The amount you are quoted may differ from the published price for a number of reasons:

    • The Consultant you choose
    • Your medical history and whether you have any associated medical conditions which may impact this treatment
    • The type of anaesthetic your Consultant advises is best for you
    • The type of implant or drug you choose or your Consultant advises is best for you


    In some cases, if you have certain pre-existing medical conditions, it may not be possible to provide you with a fixed price for your Main Treatment. If this is the case, the hospital will discuss the available options with you. Your quote is also subject to pre-assessment checks prior to your admission to hospital.

Our Consultants

  • Professor David Kerrigan

    • Band on Bypass
    • Duodenal Switch
    • Gastric Band
    • Gastric Bypass
    • Gastric Sleeve
  • Mrs Kalpana Devalia

    MBBS MS FRCS (Ed) FRCS (Gen Surg)

    • Gallbladder Removal (Cholecystectomy)
    • Gastric Band
    • Gastric Bypass
    • Gastric Sleeve
    • Inguinal Hernia Repair
  • Midhat Siddiqui

    MBChB (Bristol) 1983, FRCS ( Eng, Edin. & Glasg.), FRCS Gen.Surg.

    • Anti-reflux surgery
    • Gallbladder Removal (Cholecystectomy)
    • Gastric Band
    • Gastric Bypass
    • Gastric Sleeve
    • Inguinal Hernia Repair
  • Mr Sanjoy Basu

    MS, FRCS (Ed), FRCS (Glasg), FRCS (General)

    • Anti-reflux surgery
    • Gallbladder Removal (Cholecystectomy)
    • Gastric Band
    • Gastric Bypass
    • Gastric Sleeve
    • Inguinal Hernia Repair