If you've ever wondered why it's almost impossible to keep the weight off after a spell of dieting, US experts believe it could have something to do with stress - especially if you've lost a lot of weight quickly.
Writing in The Journal of Neuroscience, the researchers carried out tests on lab mice and found the mice that had previously been put on a strict diet ate more fatty foods than other mice who had never dieted.
In other words, going on a diet may change your natural eating behaviour. And the reason for that, say the scientists, may have something to do with stress.
The dieting mice, they explain, had increased levels of the stress hormone corticosterone. They also started behaving as though they were depressed, which led the researchers to suggest dieting may affect mood. Tell us something we don't know.
But there were also chemical changes in the dieting mice's bodies, particularly involving a stress hormone called corticotropin-releasing factor. This and other stress hormones - which were also altered in the dieting mice - are thought to control eating behaviour. And even after the mice were put back on a normal diet, the chemical changes remained.
The researchers then discovered that whenever the mice were confronted with a stressful situation, they binged on high-fat food - suggesting the changes in their bodies while dieting made them want to comfort eat.
Some earlier studies, however, say stress doesn't affect your weight, while others have a variety of theories why people pile on the pounds.
So what do you think?