Sleep-Restrictions, Late Bedtimes Cause Weight Gain
(HealthDay News) – Sleep-restricted adults with late bedtimes may gain more weight due to an overall increased caloric intake and a higher late-night calorie consumption, according to a study published in the July issue of SLEEP.
Andrea M. Spaeth, from the University of Pennsylvania in Philadelphia, and colleagues examined the effect of sleep restriction on weight gain, daily caloric intake, and meal timing among 225 healthy adults aged 22–50 years. Participants included 198 sleep-restricted adults (31 with caloric data available) and 27 control subjects (six with caloric intake data available). Caloric intake and meal times were assessed across days following an experimental condition (two baseline nights, five nights of sleep restriction [from 4– 8 a.m.], and two recovery days), or across days following control condition nights.
The researchers found that, compared with controls, sleep-restricted adults gained significantly more weight (0.97 ± 1.4kg vs. 0.11 ± 1.9kg). Among those who were sleep-restricted, African-Americans and males gained significant more weight than Caucasians and females, respectively. During days with delayed bedtime, sleep-restricted subjects consumed extra calories compared with controls who did not consume additional calories on corresponding days. Increased daily caloric intake among sleep-restricted subjects was due to more meals and additional caloric intake during late-night hours (10–4 a.m.). During late-night hours, the percentage of calories derived from fat was significantly higher than during daytime or evening hours.
"Chronically sleep-restricted subjects with late bedtimes may be more susceptible to weight gain and obesity due to overall greater caloric intake as well as increased consumption during late-night hours," the authors write.
One author disclosed financial ties to Mars Inc.