Brown fat recruited in fight on weight

THE most popular type of weight-loss surgery does not simply work by making a person’s stomach smaller, Australian researchers have found.

In research to be presented this week, Melbourne scientists have found gastric sleeve surgery activates the brain and recruits the “good fat” in the body to burn energy and contribute to its success.

The Monash University researchers are working on ways to harness the weightloss power of the nervous system driven process without the need for the radical surgery, so more Australians can access non-surgical approaches for keeping the weight off.

About 25,000 Australians had sleeve gastrectomy this year, the most common bariatric surgery, in which up to 80 per cent of their stomach is surgically removed.

Aneta Stefanidis, from the Monash Biomedicine Discovery Institute, will present pre-clinical data at the Australasian Neuroscience Society’s annual scientific meeting in Brisbane tomorrow, showing the surgery triggers the recruitment and activation of brown fat to expend energy.

Babies have ample stores of brown fat, which burns energy rather than stores it like white fat. But a decade ago it was found it also exists in smaller amounts in the shoulders and neck of adults, sparking a research race to harness these fat cells for weight loss.

“We have been able to show that if you remove the impact of brown fat, we see up to a 50 per cent reduction in the body weight loss that occurs following the gastric sleeve,” Dr Stefanidis said.

“Just days following gastric sleeve surgery we see an activation of brown fat, even before substantial weight loss . . . suggesting there are mechanisms independent of weight loss engaging the recruitment of brown fat.”

Despite the gastric sleeve surgery removing most of the stomach, the nerve communication between the gut and the brain persists.

Dr Stefanidis said the work had shown recruitment of brown fat most likely happened through this gut-brain communication via the vagus nerve, one of the most important nerves in the body.

Implantable devices that stimulate the nerve are already used, or are in research development, to treat conditions such as epilepsy, gastrointestinal conditions and headaches.

As the Monash team is now working with colleagues at The Alfred to see whether their findings in animals can be replicated in human patients, they are also working to stimulate the different nerve fibres to unlock the best target for replicating the effects of gastric sleeve surgery.