If you’ve ever wondered how bariatric surgery facilitates significant and lasting weight loss, this blog is for you. Clinical Director of Streamline and Bariatric Surgeon, Shaw Somers, explores how bariatric surgery works, looking at how the procedures reduce stomach size, alter digestion, and impact metabolic processes to promote sustainable weight management.
Whether you’re considering bariatric surgery or just curious about how it works, join us as we explore and clarify the remarkable effectiveness of these advanced surgical techniques.
What is bariatric surgery?
Bariatric surgery is essentially another term for weight loss surgery, referring to a group of surgical procedures designed to help people lose weight by making changes to their digestive system. The most common types of bariatric surgery include gastric bypass, gastric sleeve and gastric band. Each of these procedures has a unique approach, but they all aim to reduce the stomach’s capacity and/or alter the digestive process.
How does bariatric surgery work?
There are 5 different ways in which bariatric surgery works:
1. Restriction of food volume
When we reduce the size of the stomach, there is clearly less room for food and drink. This effect is strongest in the first year or so after surgery, but fades thereafter, except with a gastric band, where the effect can be adjusted.
2. Changes to the ‘sensation’ of food
We call this satiety, the sensation of satisfaction and that you have ‘had enough’ to eat. This satisfaction feeling helps leave extra food on the plate and strongly reduces hunger cravings. Research has shown this to be due to nerves in the stomach sensing the amount and type of food in the stomach. Bariatric surgery increases the amount of sensing signals so that the brain senses that you have eaten enough food much sooner.
3. Changes to your internal digestion hormones
We know that when you eat, the stomach and duodenum secretes a whole ‘orchestra’ of hormones that help regulate digestion and the metabolism, these hormones change markedly after a gastric bypass, a little less with the gastric sleeve and only slightly with the gastric band or gastric balloon. The hormone changes help the body regulate the digestive process and also change the metabolism in response to food. Normally, when we eat excess food, the metabolism should ‘fire up’ to burn this off. We now understand that with obesity, genetic and environmental factors stop this happening, so instead of burning off excess calories, they are stored as fat. The hormone changes after gastric bypass reverse this disorder, the sleeve to a lesser extent and the band only slightly.
4. Changes to the digestive process
We used to think that bariatric surgery worked by causing malabsorption. We now know that this is generally untrue. Some food elements are reduced in their absorption, such as Vitamin B12, iron, folate and calcium. This is why supplements are essential for maintaining good health in the long term. With bariatric surgery, what seems to happen is that the efficiency of food digestion by your digestive enzymes is altered, so that the signals from your intestines (yes, more signals!) tell your body to stop eating and that you have had enough. Only with the more major procedures such as duodenal switch and SADI/s is there proper malabsorption, so that food is not digested and absorbed properly. This leads to long term nutritional problems and health issues. This is why these procedures are not popular (with patients or surgeons!).
5. Changes to the body’s microbiome
Recently, research has shown that the body is host to trillions of friendly bacteria, mostly living in the gut and known as your Microbiome. This Microbiome was thought to be fairly inert. We now know that the composition and health of your Microbiome is vital to the function of almost every system in the body. It can be responsible for depression, heart disease, diabetes, and obesity. If your Microbiome is unhealthy, then you will be unhealthy. We are now discovering which bacteria are friendly, and what we can do to help these bacteria when there is an unhealthy Microbiome.
