We’ve all experienced the feeling of starting a day without enough sleep. Maybe circumstances out of your control kept you awake, such as a bout of insomnia or needing to care for a sick child. Or maybe you stayed up too late binge-watching a new Netflix series or reading an engaging book.
Whatever the reason, a sleep deficit leaves you feeling out of sorts. You may feel groggy and irritable, or even suffer a more concrete physical symptom like a headache.
A new systematic review by researchers from King’s College in London found another symptom of sleep deprivation—overeating. The review is small—11 studies and a total of 172 participants. But it found concrete evidence that partial sleep deprivation has a significant relation to the number of calories people consume the next day.
Specifically, the review found that people who slept between 3.5 and 5.5 hours per night consumed, on average, 385 calories more the next day compared to people who slept for between seven and 12 hours. That’s approximately the number of calories in a McDonald’s double cheeseburger.
In addition, people who didn’t get enough sleep were more likely to consume more fat and less protein the following day. Carbohydrate consumption [CC1] was approximately the same among the two groups.
Two earlier systematic reviews came to the same conclusion: A review in the journal Obesity about the effects of sleep deprivation on appetite found that missing out on sleep is associated with weight gain through increased appetite and decreased physical activity, a relationship that is strongest for youth and young adults.
An earlier review, published in 2007, included 17 studies and found a clear association between a shortened night’s sleep and increased risk of childhood obesity. Children who slept less had a 58 percent higher risk for obesity, with a larger risk for boys than girls.
What happens when you don’t get enough sleep? Researchers believe that a lack of sleep alters the release of two hormones that help your body to regulate feelings of hunger. When you don’t get enough sleep, your body releases more ghrelin, which stimulates appetite, and release less leptin, which suppresses appetite. This could lead to an afternoon trip to the vending machine for a candy bar or a visit to the coffee shop for a drink filled with fat and sugar.
So how much sleep should you get? The consensus is that most adults need at least seven hours per night. Without it, you may be more likely to overeat, which can lead to weight gain and a host of other health problems.