The new research by scientists at the University of South Australia has revealed that though their appetites had decreased the study participants gained weight when their sleep was restricted.
The researchers say despite free access to food, sleep restriction resulted in a decrease in appetite, food cravings and food consumption but the participants nevertheless gained weight over the 11 day course of the study which they say suggests that sleep restriction causes energy intake to exceed energy expenditure.
The study involved 92 healthy individuals between the ages of 22 and 45 years and 52 of them, all men, participated in laboratory controlled sleep restriction which involved two nights of baseline sleep (10 hours in bed per night), five nights of sleep restriction and varying recovery for four nights - 9 well rested participants served as controls - participants had three regular meals per day and access to healthy snacks, and during nights of sleep restriction subjects were given a small sandwich at one a.m.
The study found that more than 70% of the sleep deprived participants said their appetite decreased by day 5 of the study but they experienced an average weight gain of 1.31kg over the study period regardless of a change in their appetite and food consumption.
According to lead investigator Siobhan Banks, PhD, a research fellow at the University of South Australia and former assistant research professor at the University of Pennsylvania School of Medicine, a control group of well rested subjects did not experience the weight gain.
Dr. Banks says it was a surprise that participants did not crave foods rich in carbohydrates after sleep restriction, as previous research suggested they might and the results indicate that even though physiologically the desire to eat was not increased by sleep loss in participants, other factors such as the sedentary environment of the laboratory and the ability to snack for longer due to reduction in time spent asleep might have influenced the weight gain.
Dr. Banks says during real-world periods of sleep restriction such as during shift work, people should plan their calorie intake over the time they will be awake, eating small, healthy meals and healthy low fat/sugar snacks should be available so the temptation to eat comfort foods is reduced.
She says keeping up regular exercise is just as important as what food is eaten, so even though people may feel tried, exercising will help regulate energy intake balance.
The findings were presented on June 8 at SLEEP 2009, the 23rd Annual Meeting of the Associated Professional Sleep Societies.
