Starvation or fasting reduces feelings of tiredness and the need to sleep, according to research into fruit flies. Scientists have recognised the relationship between sleep and dietary metabolism for some time, and evidence that inadequate sleep increases risk of obesity, diabetes and coronary heart disease has been well explored. But this research highlighted the relationship between sleep and lipids – fatty molecules that include cholesterol and are involved in energy storage.
Paul Shaw, author of the paper published in PLoS Biology in 2010 and assistant professor of neurobiology and anatomy at Washington University in St Louis said: “The major drugs we have to either put people to sleep or keep them awake are all targeted to a small number of pathways in the brain, all of them having to do with neurotransmission. Modifying lipid processing with drugs may provide us with a new way of tackling sleep problems that is more effective or has fewer side effects.”
Shaw showed that fruit flies deprived of sleep one day will try to make up for it by sleeping more the following day. This is called sleep debt and is common in humans. Sleep deprived flies also perform poorly on a simple test of learning ability. Starvation allows the need to eat to push aside the need for sleep.
Like humans, fruit flies cannot survive without sleep. But in flies bred to be more susceptible to sleep deprivation, starvation nearly tripled the amount of time they could survive without sleep. Scientists tested the starving, sleepless flies for two markers of sleep debt: an enzyme in saliva and the flies’ ability to learn to associate a light with an unpleasant stimulus. Both tests showed that the starving flies were not getting sleepy.
“From an evolutionary perspective, this makes sense,” says Matt Thimgan, a postdoctoral research associate. “If you’re starving, you want to make sure you’re on the top of your game cognitively, to improve your chances of finding food rather than becoming food for someone else.”
So fasting can delay the onset of tiredness, keeping us awake to allow us more time to search for food. Useful for survival in lean times. Calling this is ‘producing profound mental clarity’ might be a stretch, but certainly as a survival technique it is a very important one. It might be too soon to begin fasting in an attempt to increase your mental awareness based on this research into fruit flies. The most likely application of this study is, as Shaw highlights, into drugs targeted at the genes controlling these lipids production for use in sleep medication.
Image: Martin Sharman/ Flickr
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