When you think about maintaining a leaner, healthier body, you probably think about what you eat and where you eat – but what about when you eat?
New research in the American Journal of Clinical Nutrition suggests that listening to your own body clock and eating more in accord with its schedule may be an effective way to prevent weight gain.
For the study, 110 college students helped document their sleeping and circadian behaviors for 30 days. For 7 consecutive days, they used a phone app to record everything they ate. Lab assessments were done to monitor body composition and the timing of melatonin release. (Melatonin is a hormone that regulates sleep and wakefulness, keeping the body’s circadian rhythms in sync.)
Analyzing the data, the researchers found that those with more body fat were found to eat about an hour closer to the time of their biological night.
These results provide evidence that the consumption of food during the circadian evening and/or night, independent of more traditional risk factors such as amount or content of food intake and activity level, plays an important role in body composition.
While the study leaves us wanting more research, particularly with a more diverse group, it does suggest that eating earlier in the evening – up to 4 or 5 hours before sleep – could be a help in managing weight. (Maybe our grandparents weren’t so crazy, eating supper at 5pm!)
And this, in turn, could be a help for the vast number of health issues that are linked with obesity, which remains on the rise. These include diabetes, depression, and, periodontal (gum) disease. (All of these, like obesity itself, are also associated with each other. One common denominator? Chronic inflammation.)
Of course, traditional medicine has long taught that we shouldn’t eat close to the time for sleep. Ayurveda, for instance, recommends eating your last meal of the day before 8pm – and a lighter meal, at that – and nothing at all after 10pm. It makes sense: Sneaking a midnight snack is just one more way to disrupt your circadian rhythms.
It’s also important to remember that messing with one system in the body can have a domino effect on all its other systems. By ignoring our body’s natural cues, we confuse all of the other systems, as well.
Consider what happens, for instance, if we eat late or in the middle of the night. The master clock — which is set by the light-dark cycle — is cuing all other clocks in the body that it’s night. Time to rest.
“The clock in the brain is sending signals saying: Do not eat, do not eat!” says [circadian scientist Fred] Turek.
But when we override this signal and eat anyway, the clock in the pancreas, for instance, has to start releasing insulin to deal with the meal. And, research suggests, this late-night munching may start to reset the clock in the organ. The result? Competing time cues.
“The pancreas is listening to signals related to food intake. But that’s out of sync with what the brain is telling it to do,” says Turek. “So if we’re sending signals to those organs at the wrong time of day — such as eating at the wrong time of day — [we’re] upsetting the balance.”
Learn more more about your own sleep/wake rhythm – and get some great tips on avoiding sleep disrupters – from Harvard’s Division of Sleep Medicine.
Image by Leonardo D’Amico, via Flickr