Your little ones may need those extra Z's each night to ward off excess weight. A new study finds that children who routinely don't get enough shut eye may gain unnecessary pounds. More than one thousand children were followed from 6 months of age to 7 years. Researchers kept track of how much sleep the children got and compared it to normal sleeping levels per age group. They found those that slept the least gained the most weight and 7 year old's that got enough sleep averaged 10 hours a night. It's one of the most comprehensive studies to look at weight gain in young children. Researchers say another huge factor to influence weight gain in children is the number of hours spent watching TV. The study highlights the importance of raising awareness of health sleeping as a part of obesity prevention.