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Scientists have discovered a hormone that can switch off food cravings in mice, raising hopes it could help overweight humans beat the bulge.
Researchers from the Garvan Institute in Sydney found the hormone, produced by the gut, could also have uses for people with the opposite problem - those losing too much weight.
The hormone peptide known as PYY is released into the blood after a meal, signalling to the brain that the body is no longer hungry.
Neuroscientists genetically engineered mice to produce more of the hormone and found the creatures lost weight and kept it off long term.
The results suggest it could potentially be used as a natural weight loss medication that would have fewer side-effects than current drugs, according to the study published in the international journal Neuropeptides.
Authors Professor Herbert Herzog and Dr Amanda Sainsbury-Salis said it was still unclear whether humans would respond the same way, or if the result could be long-lasting.
"At a time when people are considering radical treatments for obesity, including surgical intervention, we're very pleased to have identified a more natural alternative," Dr Sainsbury-Salis said.
The hormone was also found to significantly improve a person's ability to clear glucose, or sugar, from the blood.
"It should have the ability to prevent glucose intolerance, a known precursor of type 2 diabetes," she said.
There were also indications that by blocking PYY, appetite could be increased in people with anorexia nervosa or late-stage cancer who were losing weight.
The researchers warned it was likely to be some years before any PYY-like products reached the market.
But in the meantime, the findings were throwing up some useful clues on how individuals could help maximise their PYY levels.
"Adequate food and nutrients are required to stimulate PYY release," Dr Sainsbury-Salis said.
"This highlights the importance of weight loss regimes that don't leave you feeling hungry."
- AAP