Gaining weight is not just the result of the number of calories eaten but also may have to do with the time of day those calories are consumed, at least in mice.

The researchers, from the Salk Institute in California and elsewhere, fed the mice a high-fat diet or a standard diet. Some of the mice were allowed to eat only within an eight-hour period each day and the others were given an unrestricted amount of time to eat.

When mice on the high-fat diet were restricted to eating within eight hours, they consumed just as much as those on the same diet who were permitted to eat around the clock. However, the mice with unrestricted eating times were more likely to become obese or have other metabolic disorders.

The findings suggest that food may be better processed by the body when eating is restricted to confined hours of the day, the researchers said.