Stop reading this and go to bed!

Because only smart, well-informed people read the Real Fitness Nerd, you already know that late bedtimes can cause diet problems, given a lack of sleep stimulates production of the hormone ghrelin, which tells you to eat, while decreasing the hormone leptin, which tells you to stop eating. But now, adding to this bad case of hormonal hokey pokey, a new mini-study presented at a meeting of the Associated Professional Sleep Societies shows that tired people are less-likely to listen to their front-brain when it says, "Put down the cheesecake, smart guy."

From Health Day:

In the new study of 12 adults aged 19 to 45, people who were sleepy during the daytime showed decreased activation in the part of their brain that inhibits behavior (prefrontal cortex) when they were shown photos of high-calorie foods such as hamburgers, French fries, pizza, cakes and ice cream, compared with images of low-calorie, healthier foods.

"When you are sleepy, there's a good chance that you won't be able to control how much you eat," said lead study author William Killgore, an assistant professor of psychology at Harvard Medical School and McLean Hospital in Belmont, Mass. "You may be drawn to unhealthy foods because you are not putting the brakes on as well as you would be if you were well-rested."

So now that the "what," "where," and "when" seem to be fleshed out, I'm pondering the "why." My guess is that this dietary "minus" was actually a "plus" from an evolutionary perspective. Back the day, if a caveman wasn't getting the sleep he needed, it meant there was some serious shit goin' down, like maybe a sabertooth tigersaurus had moved into the family cave, or maybe an unplanned Ice Age had dropped in, making hunting more of a challenge. Either way, Gork needed to take care of business and sleep just wasn't on the menu. A desire for extra grub gave him the extra fuel he needed to chase wild game or negotiate with the home realtorsaurus.

Conversely, in the modern age, whatever activities we feel compelled to do after bedtime rarely burn many calories - we all generally overeat whether we sleep or not - so it's working against us. And by the way, if anyone out there thinks that whatever you're doing late night is as important as what Gork was doing, you're probably wrong. If Gork didn't find food or shelter, he would die, as would Gorkette and Gork Jr. You, however, won't die if that spreadsheet isn't sent to Corporate by 2am or if you miss the season finale of The Real Housewives of South Dakota.

I'm as guilty as anyone. After a full day of work, exercise, and child-rearing, I often stay up too late simply because I really want some time to hang out, watch TV, read, or look at William Shatner sing "Common People" on Youtube. But that doesn't make it right.

Well, except the William Shatner part. That's extremely right. But you get the point.