Researchers followed more than 1,000 children from ages 6 months to 7 years. Scientists kept track of how much sleep the children got and compared it to normal sleep levels for each age group.
The study, published in "Pediatrics," found children who grew up chronically sleep deprived were heavier than 7-year-olds who got enough sleep, roughly 10 hours on average. Those who slept the least gained the most weight.
This is one of the most comprehensive studies looking at sleep and weight gain in young children. Unlike other studies, this one did not find a precise age when a lack of sleep caused weight gain. Insufficient sleep at any time during early childhood was detrimental.
There are other factors that can influence weight gain in childhood, of course, such as the number of hours spent watching TV, but when this was taken into account the link between lack of sleep and weight gain remained.
Researchers say more needs to be done to promote healthy sleeping as part of obesity prevention.