Ever wondered why you can’t keep your hands off that junk food? A new study has found that sleep loss may be the culprit.

For many years, experts have been making the connection between sleep loss and overeating, weight gain and bad food choices. Now a new study from the University of Chicago has found that sleep loss can increase the chemical signal in our blood that allow us to gain please from salty, sweet, and high-fat foods.

The medical study, published in the journal SLEEP, found that sleep-deprived participants developed a burning desire to eat what the researchers called “highly palatable, rewarding snacks,” such as sweets and crisps, even after eating a high-calorie meal.

The evening “munchies”

The researcher also found that the participants were more likely to reach for unhealthy snacks in late afternoon and early evening – the snack times most associated with weight gain.

Erin Hanlon, PhD, a research associate at the University of Chicago, said: “We found that sleep restriction boosts a signal that may increase the hedonic aspect of food intake, the pleasure and satisfaction gained from eating.”

She added that sleep loss seems to fuel the “endocannabinoid system,” which is the same system that responds to the active ingredient of marijuana. This would explain why sleep loss seems to give you the munchies!

While this chemical signal, known as 2-AG, should peak at around 12.30pm and stay low during the night, people who suffering from sleep loss have elevated levels throughout the evening.

In practice, this lead to the sleep-deprived study subjects eating nearly twice as much fat as when they had slept for eight hours.

Hanlon explains: “If you have a Snickers bar, and you’ve had enough sleep, you can control your natural response. But if you’re sleep deprived, your hedonic drive for certain foods gets stronger, and your ability to resist them may be impaired. So you are more likely to eat it. Do that again and again, and you pack on the pounds.”

Toxic Sleep

Sleep loss has become a common problem in the UK. According to The Sleep Council’s ‘Toxic Sleep’ survey, almost half of us are getting six hours sleep or less a night. And four out of five people complain about inadequate sleep.

So, what do you do if you aren’t getting enough sleep at night? Gregg Jacobs, of the Sleep Disorders Centre at the University of Massachusetts Medical School, says that grabbing a 20 minute nap will give you as much energy as two cups of coffee, but with longer lasting effects.

Buying a new mattress could also make a big difference to the quality of your sleep. A research project carried out by the Sleep Council and Dr Chris Idzikowski found that people who find their mattress uncomfortable sleep for nearly one hour less than those who love their bed.