Even with extensive obesity prevention efforts in the past decade,
childhood obesity remains an epidemic. In 2014, 23% of American
children under the age of five years were overweight or obese. Childhood obesity increases the risk for later life chronic
illnesses like diabetes and is associated with low self-esteem and
depression. Overweight youth are about four times more likely to be
obese as adults.
In a study, the preschoolers, all regular afternoon nappers, were deprived of
roughly three hours of sleep on one day. They had no afternoon nap and
were kept up for about two hours past their normal bedtime - before
being awakened at their regularly scheduled times the next morning.
‘During the day of lost sleep, the three- and four-year-olds consumed about 20% more calories than usual, 25% more sugar and 26% more carbohydrates.’
During the day of lost sleep, the three- and four-year-olds consumed about
20% more calories than usual, 25% more sugar and 26% more carbohydrates, said Assistant Professor Monique
LeBourgeois, lead study author. The following day, the kids were allowed
to sleep as much as they needed. On this "recovery day," they returned
to normal baseline levels of sugar and carbohydrate consumption, but
still consumed 14% more calories and 23% more fat than
"With this study design, children missed a daytime nap and stayed up
late, which mimics one way that children lose sleep in the real world,"
said LeBourgeois of the Department of Integrative Physiology. According
to the National Sleep Foundation, about 30% of preschoolers do
not get enough sleep.
"We found that sleep loss increased the dietary intake of
preschoolers on both the day of and the day after restricted sleep," she
said. These results may shed light on how sleep loss can increase
weight gain and why a number of large studies show that preschoolers who
do not get enough sleep are more likely to be obese as a child and
later in life.
A paper on the study was published in the Journal of Sleep Research
"We think one of the beauties of this study is that parents were
given no instructions regarding the kind or amount of food or beverages
to provide their children," said LeBourgeois. Parents fed their children
just like they would on any normal day.
The researchers also studied each child across all study conditions -
meaning when their sleep was optimized, restricted and recovered -
which gave them control over how kids could differ individually in their
eating preferences and sleep.
The children in the study - five girls and five boys - each wore
small activity sensors on their wrists to measure time in bed, sleep
duration and sleep quality. Parents logged all food and beverages
consumed by the preschoolers, including portion sizes, brand names and
quantities, using household measures like grams, teaspoons and cups. For
homemade dishes parents recorded ingredients, quantities and cooking
"To our knowledge, this is the first published study to
experimentally measure the effects of sleep loss on food consumption in
preschool children," said Elsa Mullins, the study first author and a CU
Boulder researcher who worked with LeBourgeois as an undergraduate. "Our
results are consistent with those from other studies of adults and
adolescents, showing increased caloric intake on days that subjects were
sleep deprived," she said.
Other CU Boulder co-authors include Professor Kenneth Wright,
graduate student Sherin Cherian and postdoctoral fellow Salome Kurth.
University of Michigan co-authors include Dr. Julie Lumeng and Associate
Professor Alison Miller.
The new study opens the door for a number of follow-up studies using
larger samples, experimentally controlling dietary intake and
objectively measuring energy expenditure in children. The study was
funded in part by a National Institute of Mental Health grant to
LeBourgeois and undergraduate research grants to Mullins from CU
Another study involving Kurth and LeBourgeois supported by a Jacobs
Foundation grant and in collaboration with Brown University was recently
published in Frontiers in Human Neuroscience
. Findings showed that the developing brain regions of school-age children are the hardest hit by sleep restriction.