Five-year-olds who drink sugar-sweetened sodas, sports drinks or juices every day are more likely to be obese than those who have sugar-sweetened beverages less often, according to a new study.
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.
About 15 percent of five-year-olds in the study were obese.
Four-year-old sugary beverage drinkers also tended to have a higher rate of obesity than non-drinkers - but that finding could have been due to chance, the researchers reported Monday in Pediatrics. Among two-year-olds, there was no link between sugar-sweetened beverages and obesity.
In a statement sent to Reuters Health, the American Beverage Association trade group wrote, "Overweight and obesity are caused by an imbalance between calories consumed from all foods and beverages (total diet) and calories burned (physical activity). Therefore, it is misleading to suggest that beverage consumption is uniquely responsible for weight gain among this group of children, especially at a time in their lives when they would normally gain weight and grow."
The researchers said kids who drink sports drinks and other beverages with added sugar may not make up for the extra calories by eating or drinking less of something else. That could be in part because sugar wouldn't satisfy children's appetite as well as something with protein and fat.
Drinking milk, on the other hand, "will contribute to satiety and not as big of an increase in total intake as something that is pure sugar," DeBoer said.
His study did not take into account kids' other eating habits and physical activity.
Dr. Y. Claire Wang, who studies childhood nutrition and obesity at the Columbia University Mailman School of Public Health in New York, said she wasn't surprised by the findings.
"This is really just adding to the evidence we already know that (drinking) sugar-sweetened beverages in childhood is associated with weight gain. It's definitely one of the major, if not the main, driver in childhood obesity," Wang, who wasn't involved in the new research, said.
One of the study's co-authors, Ryan Demmer, is also a researcher at Columbia.
DeBoer said parents should be aware of where young kids are getting extra unhealthy calories and stick with water and milk for beverage options.
Wang recommended whole fruits over fruit drinks and juices.
"It's not to say that you're going to ban all these sugary things … from people's childhoods," she said. "It's just they're supposed to be very rare treats."