Australian scientists may have discovered a way to shed fat by teaching our bodies how to burn it off.
Researchers at Monash University have shown how they can switch off two specific enzymes in the brains of mice so they don't put on weight when they're fed a high-fat diet.
The study, published in the journal Cell, describes how two naturally-occurring hormones - insulin and leptin - communicate to the brain how much energy is stored in the body.
"They give the brain a comprehensive picture of the fatness of the body," said the research group leader Tony Tiganis.
The brain then sends out signals via neurons to promote the conversion of white fat, which stores calories, into brown fat, which burns calories.
The process is regulated in these neurons by enzymes, known as phosphatases. These enzymes inhibit the actions of insulin and leptin in the brain.
"In our studies we've made genetically engineered mice to lack these two enzymes and we find these mice have higher levels of brown fat," says Professor Tiganis.
Eventually, the researchers believe they may be able to help people lose weight by targeting these enzymes.
"We hope that we can harness the brain's ability to promote this browning of white fat and promote weight loss," he says.
"One mechanism may involve generating drugs that inhibit these enzymes - to flick a switch if you like to sensitise the brain to insulin and leptin."
Prof Tiganis, from the Department of Biochemistry and Molecular Biology, said if more is not done to tackle obesity it will lead to falls in overall life expectancies in countries such as the US and Australia.
"At this stage we don't fundamentally understand what is driving the obesity epidemic.
"What we do know is that obesity results from energy imbalance, where the amount of energy, as in calories, exceeds the amount we burn and need to maintain our bodies.
"So the work we've done addresses a fundamental mechanism by which energy balance and body weight may be controlled.
"The mechanism that helps to ensure that the amount of energy we consume is matched with energy expenditure so we don't put on excess weight."