Scientists said Tuesday they had found evidence that a lack of sleep causes changes in brain activity that lead to people feeling hungrier and craving more fattening foods.
Researchers have long pointed to a correlation between a steep rise in obesity in industrialised nations and a decline in sleep duration.
A causal link was suspected, but science has not been able to explain the mechanism, until now.
A team from the University of California said they used MRI (magnetic resonance imaging) scans to spot changes in the brain activity of sleep-deprived test subjects.
"These findings provide an explanatory brain mechanism by which insufficient sleep may lead to the development/maintenance of obesity," they wrote in the journal Nature Communications.
Twenty-three participants had their heads scanned twice; once after a full night of sleep and once after being deprived their shut-eye for a night -- their brain activity measured the next day as they selected items and portion sizes from pictures of 80 different food types.
Among the fatigued individuals, the researchers noted impaired activity in regions of the cortex that evaluate appetite and satiation. Simultaneously, there was a boost in areas associated with craving.
"An additionally interesting finding was that high calorie foods became more desirable to the sleep deprived participants," said study co-author Matthew Walker of the psychology department at the University of California in Berkeley.
"These findings of impaired brain activity in regions that control good judgement and decision making together with amplified activity in more reward-related brain regions fit well with, and potentially explain, the link between sleep loss, weight gain and obesity," he told AFP by email.
"Our findings indicate that (to) regularly obtain sufficient amounts of sleep may be an important factor promoting weight control, achieved by priming the brain mechanisms governing appropriate food choices."
According to the World Health Organisation, more than 1.4 billion adults aged 20 and older were overweight in 2008 -- a figure that had nearly doubled since 1980.
More than a third of adults were overweight in 2008, and 11 per cent obese, and at least 2.8 million adults die every year as a result.
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Keep Up With Your Commitments
Just like any relationship, sleeping better also requires you not to cheat -- your schedule, that is. Try to sleep around the same time each day to fall into a daily routine.
Get 7 To 8 Hours Of Sleep
They say you need seven to eight hours of sleep every day -- Cederberg says 'they' are right. She says most adults function the best with at least seven to nine hours of sleep per night.
Turn Off The Lights
To ensure a good night's sleep, make sure your room is dark. Close the curtains, turn off your lamp and the television. Cederberg says the smallest amount of light could affect your sleep -- use an eye mask if you need to.
Test Your Pillows -- Really
Cederberg suggests spending a day testing out different types of pillows, like feather or foam ones, to see which one is the best fit for you. You should never test a pillow if you're tired though -- you may just like everything in the store.
Exercising isn't only good for your health, it can give you energy throughout the day. Challenging your body will also help you rest better, Ceberberg says.
Keep Your Bedroom Clean
Make sure your room is tidy before you sleep. Switch up your linens once every two weeks, keep your room dust free and Cederberg recommends adjusting the temperature to 18 degrees Celsius for the best zZZ environment.
Block Out Noise
If you live in the city, the sounds of cars and buses may be your morning wake up call (or the annoyances keeping you up at night). Cederberg suggests using ear plugs to block out unwanted noise.
Put Your Phone Away
Another distraction before sleeping is playing with your phone or answering texts. Put your phone in another room to help fall asleep with a clear mind and not worry about a meeting the next day.
Say No To Heavy Meals
Midnight snack cravings? Try to say no. Eating heavy foods right before bed will make it harder for your body to digest and make you tired the next morning.
Find A Good Mattress
Even though pillows ensure a good night's rest -- a good mattress is just as important.