Although the link between sugary drinks and extra weight has been well documented among teens and adults, researchers said that up until now, the evidence was less clear for young children.
"Even though sugar-sweetened beverages are relatively a small percentage of the calories that children take in, that additional amount of calories did contribute to more weight gain over time," said Dr. Mark DeBoer, who led the study at the University of Virginia in Charlottesville.
He and his colleagues surveyed the parents of a nationally-representative group of 9,600 children when the kids were two, four and five years old. The children were all born in 2001. Parents reported on their income and education, as well as how often children drank sugary beverages and watched TV.
The children and their mothers were weighed at each survey visit.
The proportion of kids who had at least one soda, sports drink or sugar-sweetened juice drink each day ranged from 9 to 13 percent, depending on their age.
Those children were more likely to have an overweight mother and to watch at least two hours of TV each day at age four and five.
After accounting for those influences as well as families' socioeconomic status, the researchers found five-year-olds who had at least one sugary drink each day were 43 percent more likely to be obese than those who drank the beverages less frequently or not at all.
Kids were considered obese if they had a body mass index - a measure of weight in relation to height - above the 95th percentile for their age and gender, as calculated by the U.S. Centers for Disease Control and Prevention.
Image: Child drinking sweet beverage, via Shutterstock