Bariatric Surgery and its effect on diabetes and insulin resistance

bariatric surgery can have a positive effect on how your body uses insulin
on Wed 18 Oct


The principle behind bariatric surgery is that by altering or interrupting the digestion process through surgery, food is not broken down in the usual way and there is a therefore a reduced absorption of nutrients and calories.


It is primarily done to help individuals lose weight and there are several types of operation – usually by laparoscopy:


  • Adjustable gastric banding (AGB)
  • Roux-en-Y gastric bypass (RYGB)
  • Biliopancreatic diversion with duodenal switch (BPD-DS)
  • Vertical Sleeve gastrectomy (VSG)


It has long been acknowledged that obesity surgery indirectly helps with the management of diabetes through the subsequent loss of weight and improvement of blood sugars.


However you might be surprised to know that the surgery itself can have a directly beneficial effect on how your body uses insulin.  There are three reasons for this:


  1. It changes the way your gut hormones work which then positively affects how your body makes insulin
  2. It increases the production of bile acids which makes your body cells more sensitive to insulin
  3. It improves the way your cells use insulin which leads to lowered blood sugars.


In May 2016 bariatric surgery was officially recognised as an option for treating type 2 diabetes with new clinical guidelines stating that “obesity surgery, which was originally designed to induce weight loss should be included among the current treatment options for certain categories of people with Type 2 diabetes”


International Clinical Guidelines

Bariatric surgery can now be recommended if patients are within these guidelines:  


  • a BMI (Body Mass index) of over 40, regardless of how well their type 2 diabetes is managed, or what other diabetes treatment they are undergoing
  • a BMI of 35-40 with blood sugar levels that aren’t sufficiently controlled by following a healthy lifestyle and taking medication for Type 2 diabetes.


Surgery would also be considered if you have Type 2 diabetes, a BMI of 30-35 and your blood sugar levels are not well managed by healthy lifestyle and medication. A lower BMI threshold is recommended for Type 2 patients from an Asian background who can develop Type 2 at a lower BMI to other ethnic groups.


Controlled Studies and Trials

A recent 12 year study of the RYGB operation was concluded in the USA looking at 1156 patients split into 3 groups,  and with examinations at 2, 6 and 12 years.


The study was very positive showing “long-term durability of weight loss and effective remission and prevention of type 2 diabetes, hypertension and dyslipidaemia” (an abnormal amount of lipids).  For full details see here.


There has also been a first NHS trial of a non-invasive reversible procedure which has been developed especially for type 2 patients who require medication.


Known as the “EndoBarrier” this is a simple procedure whereby a thin plastic liner is placed at the opening of the small intestine just below the stomach and then secured.  The whole thing is done via the patient’s mouth using an endoscope - hence its name.


So far 50 NHS patients have been treated in this way and with very positive results. It is now being studied further before hopefully being reviewed by UK, European and US regulating bodies.

Here’s how the trial was reported by 


I hope you found this information helpful.


Although every effort is made to ensure that all health advice on this website is accurate and up to date it is for information purposes and should not replace a visit to your doctor or health care professional.

As the advice is general in nature rather than specific to individuals Dr Vanderpump cannot accept any liability for actions arising from its use nor can he be held responsible for the content of any pages referenced by an external link.



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