The deep-rooted reasons behind the late-night snack
Published on 17/6/2013
Don't be surprised if your appetite and your cravings grow as evening falls.
A recent study conducted by researchers at Oregon Health&Science University and Harvard Medical School reveals that nighttime appetites served a very specific function for our ancestors: stocking up on energy for the body during the night, thereby improving the chances of survival in eras when food scarcity was the rule.
The study, conducted on 12 adults, seems to have demonstrated that the hunger/fasting and sleep/wake relationship is deeply regulated by the (circadian) biorhythm, whose appetite curve reaches its lowest point in the morning and its peak in the evening. So far, an ancestral behavior that would still characterize our human species.
The evening appetite expresses the necessary accumulation of energy in view of the prolonged fast that precedes the sleep phase and lasts until waking.
The forward shift of the sleep phase induced by contemporary society (electric light, forms of entertainment) would prolong that peak phase of appetite, which today is partly responsible for the rise in cases of obesity.
The combination of technology (the refrigerator), social behaviors (delayed bedtimes) and the human biorhythm therefore seems to offer, at least in part, a reasonable explanation for the rise in obesity.