Eating late isn't great for your weight.

I've long thought night eating to be a bad idea. Not only does it interrupt sleep cycles, but as both Fred Flintstone and Gilligan can attest, it gives you weird dreams.

Now there's another reason to avoid that midnight Del Taco run -- it'll make ya fat.

A new study out of Northwestern University separated mice into two groups and fed them both high-fat diets. They allowed half the mice to eat at night -- the normal time for the nocturnal rodents. The other group ate during the day, when they'd normally be sleeping. By the end of the study, the night eaters had a 20% weight increase and the day eaters went up 48%.

Deanna Arble, the study's lead author, had this to say to WebMD:

Arble can't say for sure why the mice that ate at the ''wrong'' time gained so much more weight. ''We speculate that it's the interplay between body temperature, metabolic hormones such as leptin, and the sleep-wake cycle," she says.

For humans, nighttime is a time for rest, as the body temperature declines, she says. "Eating at night is contradicting your body's natural circadian rhythm,'' she says. "The leptin levels are starting to rise, and are supposed to be discouraging you from eating." Rising leptin levels suppress appetite.

Um, of course. That's just what I was about to say. I think I'll just stick with the weird dream thing for now. I just did my own study and more Americans identify with The Flintstones than they do with leptin and circadian rhythms.