Curbing eating after 8 p.m. could help prevent weight gain, according to a new study.
The study, published in Obesity journal, suggests that people who stay up late and sleep in tend to have worse diets, eat more at night and gain more weight, compared with those who go to bed at a reasonable hour, Time's Healthland reports.
The study followed 51 people (23 late sleepers and 28 normal sleepers) for a week and asked them to record their food intake and times, and to wear a wrist actigraph that monitored their sleep and wake cycles.
Time Healthland reports:
On average, the late sleepers went to bed at 3:45 a.m., awoke by 10:45 a.m., ate breakfast at noon, lunch at 2:30 p.m., dinner at 8:15 p.m. and had their final meal at 10 p.m. Normal sleepers, by contrast, were asleep by 12:30 a.m., woke up around 8 a.m., had breakfast by 9 a.m., lunch at 1 p.m., dinner at 7 p.m. and their last snack around 8:30 p.m.
Being a night owl appeared to do more harm than good: for starters, people who stayed up late got less sleep overall (5 hrs. 33 mins. versus 6 hrs. 38 mins. for normal sleepers). Worse, compared with early-to-bed-early-to-risers, late sleepers had a much less healthful diet: they ate more fast food (five meals per week, compared with the normal sleepers' three), drank more full-calorie soda (4.5 servings per week versus 1.3) and got significantly fewer fruits and vegetables (1.9 servings per day versus 3.4).
Notably, the late sleepers ate roughly the same number of calories per day as normal sleepers (actually, the study found that they ate 248 more calories than the normal sleepers — 2,153 calories versus 1,905 calories — but that difference wasn't statistically significant). However, they ate a larger proportion of their food later in the day — at dinner or after 8 p.m.
On average, late sleepers' dinners contained 825 calories, while the normal sleepers' suppers totaled 630 calories. Those who stayed up late consumed 754 calories per day after 8 p.m., while the normal sleepers ate only 376 calories.
The study's findings are preliminary but could have implications for people who have a hard time losing weight or for shift workers, the authors said.