A new study in the journal Obesity adds to our understanding of the link between sleep and weight. And it’s not a pretty picture for those of us who burn the midnight oil.
People in the study who habitually went to bed late and got up late in the morning consumed more calories than those who went to bed and got up early. And these were not high-quality calories, either: The late-to-bed crowd ate more fast food and less produce than those who turned in earlier.
The research, conducted at Northwestern University’s Feinberg School of Medicine and supported by the National Heart, Lung and Blood Institute, tracked 51 people (23 of them defined as “late sleepers” and 28 as “normal sleepers”) whose average age was 30. On average, the late sleepers maintained this schedule: They went to bed at 3:45 a.m. and awoke by 10:45 a.m.. They had breakfast at noon, lunch at 2:30 p.m., dinner at 8:15 p.m. and another meal at 10 p.m. Normal sleepers, on the other hand, were asleep by 12:30 a.m. and woke up by 8 a.m. They had breakfast by 9 a.m., lunch at 1 p.m., dinner at 7 p.m. and a snack at 8:30 p.m.
Those late sleepers ate an average of 248 more daily calories, twice as much fast food and half as many fruits and vegetables and more full-calorie sodas than the early-to-bed, early-to-rise contingent. And the late sleepers took in those extra calories mostly during dinner and in the late evening — after 8 p.m. Perhaps not coincidentally, consuming extra calories after 8 p.m. was linked to higher Body Mass Index.
Why this was the case is not entirely clear, though it seems to have something to do with the disruption of circadian cycles, the internal clock that is supposed to be in tune with natural rhythms of sunrise and sunset. The messing with those cycles can send many bodily systems reeling.
There could also, of course, be some underlying trait that makes people who like to eat more at night also inclined to stay up later — or vice versa.
Whatever the mechanism, I’m sure this scenario will ring true with many readers. Does it with you? Do you tend to stay up late, eat a lot in the late evening, and snooze late in the morning? Do you think that affects your overall diet and/or your weight?