The results are in from the latest weight-gain study.
Columbia University split 26 men and women into two groups. One group was allowed to sleep nine hours per night. The other was allowed only four. During this week-long study, the researchers tracked the calorie consumption of each group and found that the four-hour group ate on average 300 calories more than the nine-hour group.
The conclusion? Sleeping too little can make you eat too much.
But there are several problems with this conclusion that make me doubt the importance of this study’s results. One is the inherent shortcoming of conducting a study on only 26 people. With so few patients, deviations in calorie consumption may very well be random. If they’d studied 10,000 subjects and found the same 300 calorie discrepancy, I’d be more likely to credit the results.
Second, we don’t know how many calories these patients ate before they entered the study. Maybe the 13 people they chose to sleep-deprive ate 300 calories more on average before the study even started. Then the results would be meaningless.
But finally, and most importantly, we simply don’t know that eating 300 more calories per day, when you’re awake for five additional hours, will lead to weight gain. Weight gain isn’t only a matter of how many calories you’re taking it; it matters just as much how many calories you’re using up. And if, say, a 2000 calorie diet can be expected to sustain us for 15 waking hours (allowing for nine hours of sleep), a 2300 calorie diet may be just right to keep us going for 20 hours (allowing for four hours of sleep). In fact, 300 calories doesn’t seem like much, to keep us going for an extra 5 hours.
So I’m not sure why the researchers concluded that sleeplessness can lead to weight gain. It seems to me it may actually cause the opposite, unless we burn as many calories for each hour we’re asleep as for each hour we’re awake (which is hard to imagine).
Do you tend to gain weight when you’re short on sleep?