New York, Mar 1 (IANS): Do hunger pangs hit you at the sight of guilty pleasures like cookies, candy and chips, even after having a full-course meal? If yes, blame it on sleep deprivation.

According to a new study, lack of sleep not only leads to increased caloric intake but also stimulates changes in the hedonic aspects of food consumption.

The study showed that sleep loss initiates the process of overeating, poor food choices and leads to weight gain.

It amplifies and extends blood levels of a chemical signal that enhances the joy of eating, particularly the guilty pleasures gained from sweet or salty, high fat snack foods.

Sleep-restricted study subjects reported higher scores for hunger and stronger desire to eat. When given access to snacks, they ate nearly twice as much fat as when they had slept for eight hours.

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

The effects of sleep loss on appetite were most powerful in the late afternoon and early evening, times when snacking has been linked to weight gain, the researchers noted.

The researchers designed the study, published in the journal SLEEP, to help understand how the endocannabinoid system -- a group of endogenous cannabinoid receptors located in the mammalian brain and involved in the regulation of appetite -- connects short sleep and weight gain.

They recruited 14 healthy men and women in their 20s and monitored their hunger and eating habits in two situations: one four-day stay during which they spent 8.5 hours in bed each night (averaging 7.5 hours of sleep), and another four-day stay when they spent only 4.5 hours in bed (4.2 hours asleep).

After the period of restricted sleep, study subjects reported a significant increase in hunger levels. This was prominent soon after their second meal of the day, the time when endocannabinoid levels were the highest.

This increase in circulating endocannabinoid levels could be a mechanism by which recurrent sleep restriction results in excessive food intake, particularly in the form of snacks, despite minimal increases in energy need, the researchers maintained.

Obesity and sleep restriction have become extremely common. According to the Centres for Disease Control and Prevention, about a third of Americans get less than seven hours of sleep a night and more than a third of adults in the US are obese.