Lack of sleep leads to 'marijuana munchies' - why one feels hungry after pot

As if a lack of sleep wasn't bad enough, we have to deal with the knowledge that losing sleep is also likely to make us fat.

Researchers know there is a link between poor sleep and obesity, they just haven't understood why.

A new study published in the journal, Sleep, suggests that it is because a bad night's sleep changes our brain chemistry making us crave more energy-dense snacks such as chips, sweets and biscuits.

In fact, the researchers from the University of Chicago say, a lack of sleep sparks chemical changes similar to those of cannabis to bring a kind of "marijuana munchies" state.

"We know that marijuana activates the endocannabinoid system [ The endocannabinoid system (ECS) is a group of endogenous cannabinoid receptors located in the mammalian brain and throughout the central and peripheral nervous systems, consisting of neuromodulatory lipids and their receptors. Known as "the body’s own cannabinoid system", the ECS is involved in a variety of physiological processes including appetite, pain-sensation, mood, and memory, and in mediating the psychoactive effects of cannabis] .and causes people to overeat when they are not hungry, and they normally eat yummy sweet and fatty foods," lead researcher Eric Hanlon told the Guardian. "Sleep restriction may cause overeating by acting in the same manner."

To come to this conclusion, Hanlon and his team, took 14 healthy, non-obese men and women and split them into two groups.

Over four days, the groups' sleep and food were carefully monitored and controlled. They were given meals at 9am, 2pm and 7pm but one group slept for 7.5 hours while the other were woken after just four hours. They then swapped the groups sleeping hours. On the final night of each rotation, participants were allowed to eat whatever they wanted.

When the group was sleep deprived, they ate on average 1200kj more – about the equivalent of another small main meal.

The researchers also measured participants satiety hormone leptin, hunger hormone ghrelin, and endocannabinoids (which control of feeding, appetite, and energy balance).

They found that the sleep-deprived group's endocannabinoids, in particular one type that heightens the pleasure from eating sweet or salty foods, were elevated and stared elevated into the evening. The early-afternoon drive for hedonic eating may be stronger and last longer in a state of sleep debt.

Although the study is small and the researchers acknowledge more research is required, they say it provides an "increased understanding of the mechanisms linking insufficient sleep and the risk of weight gain [which] is important to design preventive strategies."

It is a catch-22 because separate new research has found that what we eat before bed affects the quality of our sleep. Eating crappy foods (sweets, high-carb or processed foods) before bed is more likely to lead to a bad night's sleep. Eating a high-fire (think artichokes, wholegrains, legumes, sprouts, peas, broccoli, avocado) dinner, however, is more likely to lead to a settled night's sleep.

Chew on that.