Body and Brain
As any dieter knows, there are moments when you are so hungry you could gnaw off your own arm.
Now it seems that the brain feels the same way. When starved of food, brain cells actually eat each other.
This cannibalism ramps up appetite and so could help explain who so many diets are doomed to failure.
One in four Britons is thought to be trying to lose weight at any one time.
While they may be initially successful, more than two-thirds will pile the pounds straight back on.
One explanation could come from the work of American researchers who studied a phenomenon called autophagy, in which cells ‘tidy’ their interiors by eating debris that accumulates over time.
In experiments on cells in the lab and on mice, the team from the Albert Einstein College of Medicine in New York showed that lack of food triggers autophagy in brain cells key to appetite control.
This causes the release of fats, which in turn results in higher levels of a powerful brain chemical that stimulates appetite, the journal Cell Metabolism reports.
It is thought the whole process is kick-started by hunger, with the emergency breaking down of fat stores signalling to the brain that there is a shortage of food and making it eat its own cells.
This is bad news for dieters, because going without food could make them hungrier than ever.
Researcher Dr Rajat Singh said that drugs that interfere with this process could help treat obesity, by making people ‘less hungry and burn more fat’.
The findings may also help explain why appetite tends to wane with age, as cells in the ageing body are less good at autophagy.