In an article that appeared in the journal SLEEP in February, 2016, and which was summarized in a New York Times post entitled “Poor Sleep Gives You the Munchies,” researchers report that one way that poor sleep and insomnia may lead to weight gain is that insomnia increases activity of the endocannabinoid system in the brain, the part of the brain that is activated by marijuana.
The study was a small one, there were only 14 subjects in the study. These 14 subjects and four days of normal sleep and then four days of sleep restriction and they had repeated blood draws throughout the study to assess levels of two endogenous cannabinoids.
The researchers found a strong circadian rhythm in the blood levels of both cannabinoids with a peak in late afternoon and a trough level in the middle of the night.
They also found that levels increased significantly during the restricted sleep phase of the study and that this correlated with significantly increased craving for sweet and fatty foods, particularly in the late afternoon (snack time in many work environments).
This fits with other information about the effects of endocannabinoids on taste sensation – they make sweet foods taste better – and appetite.
The subjects ate more when they were sleep deprived, but interestingly they did not eat any more at mealtimes, the increase was entirely due to larger and more frequent snacks.
“Sleep Restriction Enhances the Daily Rhythm of Circulating Levels of Endocannabinoid 2-Arachidonoylglycerol.” Erin C. Hanlon, PhD1; Esra Tasali, MD1; Rachel Leproult, PhD2; Kara L. Stuhr, BS3; Elizabeth Doncheck, BS3; Harriet de Wit, PhD4; Cecilia J. Hillard, PhD3; Eve Van Cauter, PhD1. SLEEP. VOLUME 39, ISSUE 03. 2016. http://dx.doi.org/10.5665/sleep.5546