New research has found that infants and toddlers who sleep less than 12 hours a day are twice as likely to become overweight by age 3 than children who sleep longer.
This factor combined with watching too much of television elevates the risk even further.
The scientists from Harvard Medical School say children who sleep less than 12 hours and who watch two or more hours of television each day have a 16 percent chance of becoming overweight by age 3.
Dr. Elsie Taveras, an assistant professor at Harvard's Department of Ambulatory Care and Prevention says mounting research suggests that decreased sleep time may be more hazardous to our health than first imagined and such hazardous effects are true even for young infants.
Dr. Taveras is the lead author of a long-term study of the effects of diet and other lifestyle factors on maternal and child health called Project Viva.
The researchers identified 915 mother-infant pairs from Project Viva, and recorded infant weight and measurements at a number of personal visits.
The mothers were asked to record how many hours their child slept each day on average at 6 months, 1 year, and 2 years and to report the average number of hours their children watched television on weekdays and weekends.
The research team found that the combination of low levels of sleep and high levels of television viewing appeared to be synergistic and was associated with significantly higher BMI scores and an increased risk of becoming overweight.
Watching too much television viewing is a known risk factor for children becoming overweight, and a similar link has been found between sleep restriction and overweight in older children, adolescents and adults.
Previous research with adults, adolescents and older children has shown that restricting sleep changes hormone levels, which could stimulate hunger and increase weight gain.