Bariatric surgery – not just about losing weight

Obesity has been described as a pandemic of the modern age with over 24 per cent of English adults now classed as obese. In England, over the last decade, we have seen an eight fold increase in laparoscopic bariatric surgery – minimally invasive weight loss surgery, such as gastric bypass, with no increase in mortality or unplanned readmission. Bariatric surgery has many medical benefits, but it also means profound lifestyle changes for patients. In this blog post, lead bariatric surgeon at the Trust, Mr Ahmed Ahmed explains that there is more to bariatric surgery than meets the eye.

For many of our patients, bariatric surgery isn’t just about losing weight, it will also help ‘cure’ some of their other existing medical conditions and allow them to lead a ‘normal’ life.

Gastric surgeries such as the sleeve, bypass and mini bypass cause chemical changes in the body within a few hours of the operation.

The sleeve gastrectomy operation involves converting the stomach into a long, thin tube by stapling it along its length and removing the excess stomach. The route that food takes is unchanged following this surgery, it simply reduces the amount of food that can be eaten.

In a gastric bypass, some of the stomach and part of the small intestines are bypassed. The stomach is stapled to leave a smaller pouch and then a section of the small intestine (about 100 cm down from the stomach) is attached to the small stomach pouch that has been created. In effect, only small volumes of food can then be consumed, due to the small pouch, and this food ‘misses out’ the first 100 cm of small intestine, reducing absorption.

The mini gastric bypass also works both by restricting the amount of food that can be eaten at any one time, and by reducing absorption. The main difference between the standard gastric bypass procedure and the mini gastric bypass is that there is only one ‘join’ in the mini version rather than two.

Regardless of the surgery, most patients who have suffered type two diabetes for a short duration – a common condition in patients who are obese - can usually leave hospital no longer being diabetic. This is because the surgery seems to enable the body to produce enough insulin to regulate body sugar – something it has previously been unable to do. Initially it was thought that the reduction in the patient’s weight following the surgery was the reason that the pancreas started to produce enough insulin following the surgery. But we now know that the chemical changes which essentially ‘cure’ a patient of type two diabetes happen literally overnight, before the patient has even lost any weight. This means our patients can begin to live healthier lives straight away.

The surgery also changes the levels of hormones which tell our bodies when we are hungry or full. Ghrelin, the hormone which increases our appetite and tells us we are hungry, reduces in patients following the surgery and leptin, the hormone responsible for decreasing our appetite and giving us that full feeling, increases. The changes in the hormones work in conjunction with the physical reduction of the patient’s stomach, giving them even more chance of losing weight.

Research has found that the surgery brings about changes to the microorganisms in the gut and bile too. Research with mice has shown that if you put the microorganisms found in a mouse with a healthy weight into an overweight mouse’s intestine, the overweight mouse will lose weight. This research seems to indicate, in mice at least, that the microorganisms in our gut can also help control our weight and that the makeup of those microorganisms are different in patients who are overweight and those who are a healthy weight.

While bariatric surgery can support weight loss in these different ways, patients may also encounter challenges due to the lifestyle changes it brings. At our Trust, we try to make sure our patients are psychologically ready for the surgery. All of our patients will see a psychologist regularly from referral until their operation. These sessions help the patient explore their relationship with food and prepare them for their new relationship with it. This is also a chance for us to ensure that they are mentally able to commit to the surgery. Many patients who are obese suffer with low self-esteem and depression linked to their weight. By being able to take control of their weight and work towards being a healthy weight, we see many patients report that their self-esteem increases dramatically after the surgery.

Many patients report to me that the surgery has given them a new lease of life. For these patients, doing simple things such as being able to kick a football around with their children or going fishing are possible again following the surgery. These are the things that matter most to our patients following surgery. As medical technology and knowledge continues to advance, it’s important we understand the full impact – and challenges – of new procedures and how we can achieve the best possible outcomes for our patients and our wider communities.