How to beat jet lag: don't eat, researchers suggest.

In addition to the light-driven circadian clock that regulates the body in response to changes in night and day, the mouse brain contains a second, separate clock that keeps track of mealtime, scientists say.

This clock, which resides in a different brain structure than the light-driven clock, probably takes over when food is scarce, changing the animals' behavior patterns so that they don't sleep through an opportunity to eat.