On a weight loss diet, we steer clear of fatty and sugar-laden foods. With some determination, we manage to do so but it gets difficult on certain days, mostly all those days after a sleepless night. Lack of sleep can bend our food preferences towards more sweet and high-fat foods like cheesy pizza or cakes and ice-creams. It actually does happen with most of us but till date, nobody knew the exact reason behind it and the exact mechanism that plays the role. A new Northwestern University’s medicine study, published in journal ‘eLife’ investigated this further assuming that the sense of smell tells the human brain what to eat. A sleepy nose affects the olfactory system to make the food odours stronger for the brain. Sleep deprivation could have an impact on the endocannabinoid system, a complex network of molecules in the nervous system that controls biological processes such as appetite.The team of researchers studied the effect of a four-hour night’s sleep on 25 healthy people. Their blood samples were taken the next day and it showed increased amounts of 2-oleoylglycerol, a molecule that is part of the endocannabinoid system.Surabhi Bhutani, lead author of the study said “Here we test the hypothesis that neural processing in central olfactory circuits, in tandem with the endocannabinoid system (ECS), plays a key role in mediating this relationship. We combined a partial sleep-deprivation protocol, pattern-based olfactory neuroimaging, and ad libitum food intake to test how central olfactory mechanisms alter food intake after sleep deprivation.”The sleep-deprived participants were provided the choice to eat whatever they wanted. It was seen that people with higher levels of 2-oleoylglycerol reached out to more energy-dense foods. The team realised that in these people who did not get enough sleep the night before, an odour-processing region called the piriform cortex was encoding smells more strongly.“We found that sleep restriction increased levels of the ECS compound 2-oleoylglycerol (2-OG), enhanced encoding of food odors in piriform cortex, and shifted food choices toward energy-dense food items,” Surabhi Bhutani concluded.These findings pave way for a potential neurobiological pathway that may guide changes in ECS to regulate food choices, especially to avoid weight gain.
