We’ve all heard the old adage, “Early to bed and early to rise makes a man healthy, wealthy and wise.” Of course it always made sense. When you’re well-rested, you’re functioning at a higher level, you think more clearly and are more in tune with the world around you. Today, FoodFacts.com found another reason we should all try to follow those wise words. More sleep … and better sleep may have an effect on our weight.

A study has been released from the Sleep and Chronobiology Laboratory at the Hospital of the University of Pennsylvania that suggests that healthy adults with later bedtimes and chronic sleep restriction may gain more weight than those who schedule earlier bedtimes and sleep undisturbed.

The study, which appears in the July issue of the journal SLEEP, is the largest, most diverse healthy sample studied to date under controlled laboratory conditions. Results show that sleep-restricted subjects who spent only four hours in bed from 4 a.m. until 8 a.m. for five consecutive nights gained more weight than control subjects who were in bed for ten hours each night from 10 p.m. until 8 a.m.

It’s probably not surprising that the weight increase in the sleep-restricted participants was due to an increase in the number of meals consumed during the late-night period of wakefulness. It may be surprising though, that it was also determined that during that late-night period, those subjects consumed more calories from fat than they did during daytime hours.

The study group was comprised of 225 healthy, non-obese people ranging in age from 22 to 50 years old. Participants were randomly selected for the sleep-restricted group or the control condition group and spent up to 18 consecutive days in the laboratory. Meals were served at scheduled times, and food was always available in the laboratory kitchen for participants to eat at other times of the day as they chose. Subjects could move around the lab, but were not allowed to exercise. Watching television, reading and playing video games and other sedentary activities were allowed.

Researchers noted that they were surprised to find significant weight gain during an in-laboratory study with a defined time parameter. There have been previous studies suggesting an association between short sleep duration and weight gain and/or obesity. This particular study also found gender and ethnicity differences seemed to play a role in the weight gain of sleep restricted participants.

FoodFacts.com thinks that this study information might be useful in regards to the obesity epidemic. It states fairly clearly that when people stay up later, or are wakeful at night, they are eating more. And their choices for those late night meals appear to be less healthful than the choices they are making during daytime hours. Of course, better sleep means better rest for our bodies, but it also seems to mean better food choices during our waking hours and less consumption of fatty foods when we really need to be sleeping. We should be aware of this information and conscious about our food intake when we are up late. And of course, we should make every effort to get to bed when we need to in order for our bodies to take advantage of the rejuvenation we experience from real, restful sleep.