Short-sleep food cravings show endocannabinoid effects
Young, healthy adults are more likely to crave highly palatable snacks when they are sleep-deprived than when they have slept 8 hours per night, due in part to the effect of sleep restriction on the endocannabinoid system, recent study findings show.
In a randomized crossover study of adults observed under both normal and restricted sleep conditions, researchers found that the food craving effects of sleep deprivation are similar to those caused by marijuana use.
“We found that sleep restriction boosts a signal that may increase the hedonic aspect of food intake, the pleasure and satisfaction gained from eating,” Erin Hanlon, PhD, a research associate and associate professor in endocrinology, diabetes and metabolism at the University of Chicago, said in a press release. “Sleep restriction seems to augment the endocannabinoid system, the same system targeted by the active ingredient of marijuana, to enhance the desire for food intake.”
Hanlon and colleagues analyzed data from 14 adults aged 18 to 30 years with normal glucose tolerance and no sleep disorders (11 men; mean age, 23.4 years; mean BMI, 23.9 kg/m²) tested under two sleep conditions 4 weeks apart at the University of Chicago Clinical Resource Center. Participants were assigned to 4 nights of normal sleep (8.5 hours) and 4 nights of restricted sleep (4.5 hours). Participants provided blood samples on day 3 during a 24-hour period to measure cortisol, leptin, ghrelin and endocannabinoid 2-arachidonoylglycerol (2-AG) and its structural analogue 2-oleoylglycerol (2-OG). Participants also consumed three identical carbohydrate-rich meals (20% fat, 68% carbohydrate, 12% protein) at breakfast, lunch and dinner, before fasting until the afternoon of day 4.
On the afternoon of day 4, participants were presented with a buffet of palatable foods tailored to meet their individual dietary preferences determined during an interview. Snack bars, including cookies, candy and chips, were available in the participants’ private rooms that evening, followed by a second buffet for dinner. Researchers instructed participants to consume as much as they wanted at both buffets and the snack bar, and concomitantly assessed hunger, appetite and food intake.
After a normal night’s sleep, 2-AG levels were low in the morning and peaked in the early afternoon, before decreasing.
levels rose to levels about 33% higher than those seen after normal sleep (P = .008), with peak time occurring approximately 2 hours later than under normal sleep conditions (about 9 p.m.).
Participants reported a significant increase in hunger levels, particularly after their second meal of the day, when experiencing restricted sleep. Sleep-deprived participants also expressed greater desire to eat.
Sleep-deprived participants also consumed approximately 50% kilocalories more as snacks; however, they did not significantly reduce their caloric intake at the 9:30 p.m. buffet meal vs. normal sleep participants.
“In contrast, under normal sleep conditions, the trend for lower snack intake was compensated with a significant increase in caloric intake at dinner,” the researchers wrote.
In commentary accompanying the study, Frank Scheer, PhD, of the Medical Chronobiology Program at Harvard University’s Brigham and Women’s Hospital, said the results show that sleep restriction causes changes in the hedonic aspects of food consumption.
“The orexigenic effect of endocannabinoids is proposed to be linked to the reward value of food,” Scheer wrote. “Thus, the observed increase in the peak in 2-AG following sleep restriction may be part of the mechanism by which people overeat following sleep restriction.” – by Regina Schaffer
Disclosure: The researchers report no relevant financial disclosures.
“Sleep restriction boosts a signal that may increase the hedonic aspect of food intake, the pleasure and satisfaction gained from eating.”