Lack of sleep affects food choices and if you don’t sleep well it can cause you to choose more high-calorie foods. So, not only does being overweight cause you to snore, it would appear that snoring causes you to gain weight too.
It’s obviously normal for a poor night’s sleep to affect you the next day and make you feel tired; if it’s a constant problem then it could have some wide-ranging effects on your health.
Several studies have suggested that a lack of sleep can increase the chance of weight gain and obesity. It may be that a lack of sleep affects hormones that help control our appetite, that people eat more calories to make up for the tiring effects of lost sleep, or that people who stay up late tend to sleep less overall and eat more calories during their extended waking hours.
However, these are mostly theories, as few good-quality studies have explored the link between sleep, eating, and weight gain. To help fill this gap in what we know, researchers recruited 225 healthy, non-obese people (aged 22 to 50 years old) to live in a sleep laboratory for 12 to 18 days.
They randomly selected participants to have five nights of either:
Restricted sleep, with four hours in bed, from 4 a.m. to 8 a.m., or
Unrestricted sleep, with 10 hours in bed, from 10 p.m. to 8 a.m.
During the day, people had regular meals and could also eat at other times, as food was always available in the kitchen. What food they ate and their weight were closely monitored, so the researchers could compare the two groups to see whether restricted sleep increased the chance of weight gain.
What did we learn?
People who had restricted sleep consumed more calories than those who had unrestricted sleep.
All of the extra calories – around 550 per day on average – were from food consumed between 10 p.m. and 4 a.m.
When eating late at night, people also got more of their calories from higher fat foods than at other times of the day.
On average, people with restricted sleep gained nearly a kilo of weight, while those with unrestricted sleep gained only one-tenth of a kilogram.
How reliable is the research?
This was a good-quality study. However, it’s worth noting it only included people who were healthy, fairly young, and not obese. So it’s not clear whether these findings will definitely apply to other groups of people. Also, the participants weren’t able to exercise during the study and might not have had access to all the foods they usually ate. These things might have had an effect on the findings.
What does this mean for me?
It provides good evidence that restricted sleep can increase how many calories you eat and leads to weight gain, at least in the short term. If you tend to stay up late and/or get little sleep, it may be especially pertinent to you as after 10 p.m. was when people typically got their extra calories, rather than during the day.
By John Redfern