This site uses cookies to store information on your computer. I'm fine with this Cookie information
Follow is on Twitter Like us on Facebook Follow us on Instagram
Covid-19 (Coronavirus)

Information and guidance for public, NHSGGC staff, and community-based services.  Hospital visiting restrictions now in place.


What is the criteria for weight loss surgery?

 Type 2 Diabetes

  • Diagnosis of Type 2 diabetes < 10 years
  • aged > 18 to < 55 years old
  • BMI 35 to < 55kg/m2 (if higher would aim to reduce via the programme)
  • HbA1c < 75 mmol/mol (9%)
  • Completion of 4 month (minimum) lifestyle programme via SWMS demonstrating a loss of least 5kgs  (11 pounds)
  • The surgeon will make the final decision taking into account a patients past medical history (i.e benefits vs risks)

Sleep Apnoea

  • confirmed diagnosis of sleep apnoea
  •  aged > 18 to < 45 years old
  • BMI 35 to < 60kg/m2 (if higher would aim to reduce via the programme)
  • Completion of 4 month (minimum) lifestyle programme via SWMS demonstrating a loss of least 5kgs  (11 pounds)
  • The surgeon will make the final decision taking into account a patients past medical history (i.e benefits vs risks)


Occasionally someone may be considered for surgery outside of this if they have extraordinary health or clinical issues which would be improved by weight loss surgery. This would be considered following a discussion with the patient’s own health professionals and the exceptional referral to surgery group.

(Criteria revised September 2019) 

What is the referral route for weight loss surgery?


Attendance at the SWMS is the only way to be referred for weight loss surgery.

How to refer to bariatric surgery via SWMS?


Please see our referral section


What type of surgery is offered?


  • Sleeve Gastrectomy – This involves converting your stomach into a long thin tube or ‘sleeve’ by stapling along its length in a vertical direction. The surgeon removes about 70% of your stomach during the procedure. The smaller stomach pouch or sleeve will reduce your capacity to eat large portions and should also help you feel satisfied for longer on smaller food portions. This is a permanent procedure and cannot be reversed.


  • Single anastomosis (mini) gastric bypass or Roux-en-Y gastric bypass - A smaller stomach is created which will restrict your food intake. A section (about a 1/3) of your intestine is bypassed which helps you lose weight by reducing the amount of calories your body can absorb. This reduces hunger and creates fullness quickly so the amount you can eat is less. Fewer vitamins and minerals (especially Iron) are absorbed as food passes through the intestine. This is a permanent procedure and cannot be reversed.

 Mini gastric bypass           Roux-en-Y gastric bypass


  • Laparoscopic Gastric banding (less common) - An inflatable silicone device which is placed around the top part of the stomach, creating a small pouch of stomach above the band. The band is placed round the area of the stomach where we have nerves that send satiety (fullness) signals when we are eating. After surgery, through the port (see image) small amounts of saline are injected to inflate the band. The band (with fluid in it) will apply pressure to the fullness nerves as food passes through so you should feel satisfied with less food.


What does it involve?


You will need to have laparoscopic (keyhole) surgery. You will also need to have a general anaesthetic.


What are the possible benefits of weight loss surgery?


  • Long term weight reduction
  • Improvement or remission of Type 2 Diabetes
  • Improved cholesterol levels
  • Improved Coronary Artery Disease
  • Improved Blood Pressure
  • Improved Obstructive Sleep Aponea (Disturbed sleep)
  • Improvement in Osteoarthritis
  • Improved mobility
  • Reduction in medication


What are the risks of the procedures?


General Anaesthetic Risk:

  • Blood clots in Legs (Deep Ven Thrombosis)
  • Blood Clots in Lungs (Pulmonary emboli)

Specific risks:

  • Staple Line Leak
  • Staple Line Bleed
  • Damage to Other Organs
  • Wound Infection
  • Nausea and Vomiting
  • Pain
  • Heartburn
  • Potential Open Abdominal Surgery
  • Failure To Lose weight
  • Wound site hernia
  • Sepsis
  • Mortality


Where do patients have their surgery?


Queen Elizabeth Hospital

Glasgow Royal Infirmary


How are people referred for surgery?


 If you meet the criteria outlined above and completed the 4 month lifestyle programme demonstrating a loss of least 5kgs  (11 pounds) you will be invited to a Surgery Information Session ( SIS).


Surgery Information Session

  • Delivered by bariatric Dietitian
  • What weight loss surgery is and how it helps people to lose weight long term.
  • Expected weight loss with surgery
  • Dietary and lifestyle modifications required pre and post procedure
  • Living with surgery
  • When surgery may not be the most suitable treatment option or the areas that surgery will not help with and that the patient will need to work on (with the help of SMWS team).
  • You can ask questions at the Information Session and are encouraged to consider which surgery is the right choice for you.
  • Written information will be given.
  • You are encouraged to bring a supportive relative or friend.

You do not need to make up your mind at this point and are free to attend the SIS again and enter the surgery programme at any time in the programme after you have completed Phase 1 and continue to maintain at least  5kg weight loss.

If you do decide to opt for surgery you then enter the surgery pathway as outlined below


Surgery Pathway


Dietetic Assessment


Diet changes made so far

Current meal pattern and eating routine

Current portion sizes and food and fluid choices

Eating behaviours

Social Eating

Eating habits that the patient thinks gastric surgery will help them improve

Current physical activity levels     

Completion of psychological screening measures

As part of the assessment the Surgery team will ask the patient to follow a two week low calorie trial diet. This is to encourage that the patient to make ongoing changes to their diet and behaviour that will be needed to achieve success after weight loss surgery.

Psychology Assessment

Level of psychological, social and cognitive function

Eating behaviours

The patient’s level of social support

Coping skills (for example, how the patient copes with difficult situations)

How the patient feels surgery will help them

What the patient expects from having surgery

The psychologist will advise if any psychology support or treatment would be needed for the patient before surgery.

What happens next?


If the psychologist and Dietitian feel that the patient is suitable to be put forward to the surgeons they will send a referral report to the surgeons.

The surgeon will then see the patient and assess if they are suitable for surgery in terms of past medical history and clinical risk

It is the surgeon who makes the final decision on surgery.

How does the SWMS Surgery team prepare people for weight loss surgery?


It is very important that a patient who has weight loss surgery is given the right advice and support before and after their surgery. This gives people the best chance of success.

To help patients prepare for surgery they will be asked to attend 4 fortnightly Preparation for Surgery groups focussing on dietary changes, eating behaviours and emotions and physical activity

Patients can also be seen by the surgery team physiotherapist for advice about activity or mobility issues.

Just before their operation patients will be seen one to one to be given liver reducing dietary advice.


What follow-up support is offered after surgery?


SWMS offers  intensive 2 year follow up however patients can be referred to SWMS lifelong after surgery

  • 1 week phone call from bariatric nurse
  • 4 weeks 1:1 with dietitian and surgeon
  • 8 weeks 1:1 with dietitian
  • 12 weeks 1:1 with dietitian
  • Post Surgery Education Sessions from 4 months focussing on optimising nutrition, exercise, social and psychological aspects of life with bariatric surgery
  • Monthly Surgery Support groups (optional) is a chance for surgery patients to meet and discuss their progress and issues.
  • Patient Led social media Forum
  • Patients may also be seen by the psychologist or physiotherapist after surgery if required


How much weight loss can be expected following surgery?


  • 60-65% (sleeve) of the excess body weight they are carrying
  • 70-75% (bypass)

If a patient weighs 170kg (26 stones 11 pounds). They are 1.78 metres tall (5 feet 10 inches)

Their BMI (Body Mass Index) would be 54 (kg/m²)

The healthy BMI range is 20 – 25 (kg/m²). To have a BMI of 25 this patient would need to weigh 80kg (12 stones 8 pounds)

This means this patient is carrying 90kg of excess weight (170kg minus 80kg = 90kg)

This patient’s excess body weight = 90kg

In the first two years after surgery this patient could lose 60-75% of their excess weight

How much weight a patient loses completely depends on how much they make changes to their diet, exercise levels and behaviour. Some patients can lose more weight than this; other patients may lose less weight.


What type of supplements will I need to take?


A complete multivitamin and mineral supplement should be taken plus a calcium and vitamin D supplement will be required lifelong. Iron may also be required, your dietitian will advise if this is necessary.  Intramuscular Vitamin B12 injections are also required 3 monthly lifelong.


Can people who have been through the SWMS Weight Management programme be referred again directly for surgery?


No, all patients who meet criteria must be re-referred and complete the 4 month lifestyle programme demonstrating a loss of least 5kgs (11 pounds) in their current episode of care

 Further information and useful links can be found at:

If you have any questions about weight loss surgery after reading this information please don’t hesitate to ask a member of the SWMS team.