When you look at a greasy cheeseburger, or a decadent dessert,
your brain's reward centres becomes aroused. But it gets even
more excited at the sight of unhealthy fare when you haven't had
enough sleep. This is what researchers from Columbia University
in New York City found, after putting 25 men and women of
healthy weights in a functional MRI scanner and showing them
images of food. But first, participants stayed in the lab for
five nights, either getting a nightly four hours of sleep, or an
uninterrupted slumber of up to nine hours per night. A month
later, the same participants were tested, but with their amounts
of sleep reversed. Their brains were observed as they looked at
pictures of healthy foods like fruits and vegetables, oatmeal
and yogurt, as well as unhealthy foods, including bacon
cheeseburgers, pepperoni and donuts. "Under restricted sleep,
brain activity response to unhealthy food was stronger," says
the study's lead investigator, Marie-Pierre St-Onge. "The brain
regions involved in reward a