As revealed by previous studies, lack of sleep can also lead to weight gain. Inadequate sleep could raise the hormone ghrelin that signals when to eat, and reduce hormone leptin that tells to stop eating. People who do not have enough sleep have less leptin and more ghrelin. Such imbalance of hormones can drive people to keep on eating.
On June 13, 2011, researchers from Harvard Medical School and McLean Hospital in Belmont, Mass reported at a meeting of the Associated Professional Sleep Societies in Minneapolis, Minn that people suffering from sleep deprivation are likely to be attracted to high calorie foods because these foods provide a sudden but not sustainable burst of energy.
In a paper that was published in the ‘American Journal of Clinical Nutrition’ in May 2011, researchers from Uppsala University in Sweden found that sleep deprivation could slow down metabolism causing the body to use less energy. The European study showed that lack of sleep not only cause weight gain but also slow the rate at which calories are burnt.
The explanation is that a one night of sleep deprivation could acutely reduce energy expenditure in healthy men, which suggests that sleep can regulate daytime energy expenditure in humans. The researchers therefore argued that getting plenty of sleep might prevent weight gain.
In the study, 14 male university students went through a series of sleep conditions, namely curtailed sleep, no sleep, and normal sleep, over several days. Measurements were recorded for the changes in how much they ate, their blood sugar, hormone levels and indicators of their metabolic rate.
Analysis indicated that even a single night of sleep deprivation slowed metabolism the next morning, reducing energy expenditure for tasks like breathing and digestion by 5 to 20 percent, compared with the morning after a good night's sleep. The young men also had higher morning levels of blood sugar, appetite-regulating hormones such as ghrelin, and stress hormones such as cortisol after sleep disruption.
To help people get more sleep, experts’ advice is to try to go to bed an hour earlier each night, limit caffeine and alcohol, and try to exercise 5 to 6 hours before bed.