While some people overeat when they’re bored or stressed (stress actually makes me less hungry), a lack of sleep has always been my downfall. Unfortunately, my experience (N = 1) is artisanal data. But scicurious brings some data to bear on this question (boldface mine):
The authors took 8 men and 8 women who reported getting an average of 8 hours of sleep per night into an inpatient facility. They were taken off caffeine one week before the study and were told to stick to 9 hours of sleep opportunity (stay in bed 9 hours) per night for the first week. They also were put on a diet that was calibrated exactly to maintain their current weight.
When they entered the study, they spent the first three days getting a baseline 9 hours of sleep. Then, for 5 days straight (in order to simulate a typical work week), they were limited to 5 hours of sleep per night. During that time they were allowed to eat both scheduled and unscheduled meals. Afterward, the patients were allowed to resume their baseline.
During the sleep periods, the authors measured their levels of ghrelin (which stimulates feelings of hunger), leptin (which subdues feelings of hunger), and melatonin, as well as monitoring their energy expenditure, what they ate, and how much. And of course, the participants were weighed.
What they found was that, while ghrelin was down and leptic was up during the 5 hours of sleep condition (which should mean you were LESS hungry, and in fact, the participants reported being less hungry), the participants all…gained weight. About 0.82kg, or 1.8 pounds over the course of 5 days, which is quite a bit! And they gained weight in SPITE of increase energy expenditure…
And why? They were substituting food for sleep…
The participants were taking in more food than they needed (in men, 70% more, and in women, 16% more). And the vast majority of it was carbohydrate.
Yikes. But the good news is that when they were put back on a normal sleep schedule, eating returned quickly to normal, and women actually lost a little weight.
I can’t help but think that, as hours worked increase from 1980s to current day (it jumped around a bit since 2010), we’ve helped create an environment conducive to unnecessary weight gain.
Interesting. Anecdotally, I saw the same trend in my own behavior during graduate school. Major munchies during times of sleep deprivation. The link to ghrelin/leptin levels makes sense. Certainly that could help explain “night hunger” that so many people talk about.
Of course, anything as complex as obesity has multiple genetic/epigenetic/social/environmental factors all playing their part. But your point that work hours have increased significantly since the 1980s makes sense. After all, the obesity epidemic started gaining real traction just at the time when work hours were starting to explode. It could also lend credence to the notion that the corporate mentality where downsizing jobs so that 1 person does the job of 3-5 people, may actually be killing us.