L O N D O N, Feb. 16, 2001 -- An extra soft drink a day gives a child a 60
percent greater chance of becoming obese, new research suggests.
The U.S. study, published this week in The Lancet medicaljournal, says the soft drink-obesity link is independent of thefood children eat, how much television or videos they watch and theamount they exercise.
Experts, who called the findings "enormously important," havelong believed that sweetened drinks were contributing to the risingobesity epidemic among children, but said there has been noreliable evidence of a link.
"These are estimates and the study doesn't tell us theimportance of soft drinks relative to the other factors thatcontribute to obesity, but these data suggest that people aren'tcompensating" for the extra calories by cutting back on eating,said the study's lead investigator, Dr. David Ludwig, director ofthe obesity program at Boston Children's Hospital.
France Bellisle from France's Institute of Health and MedicalResearch, said the study provided "convincing" new evidence aboutthe relationship between sugar and weight gain in children.
Obesity up 100 Percent
The prevalence of obesity among children in the United Statesincreased by 100 percent between 1980 and 1994.
A common measurement of obesity is the body mass index, or BMI,which takes into account weight and height. A BMI of 25 means aperson is overweight. The threshold for obesity is a BMI of 30.
For children, experts disagree on what constitutes obesity. Somebelieve that, in general, any child with a BMI above the 85thpercentile for age and sex is obese, while others use the 95thpercentile.
The study used the 85th percentile as the threshold for obesity.By that measure, scientists estimate that 24 percent of Americanchildren are obese. Rates of childhood obesity in Europe are not ashigh as in the United States, but are on the rise. Accuratestatistics were not readily available.
The soft drink study involved tracking 548 children aged 11 or12 from public schools across Massachusetts for two school yearsuntil May 1997.
It found that each sugared soft drink the children wereconsuming each day at the beginning of the study contributed 0.18points to their BMI.
If they increased their daily soft drink intake, each extra sodamade them 60 percent more likely to become obese, regardless of howmany sodas they were drinking before. All the children were alreadydrinking some soft drinks at the beginning of the study, but theresearchers extrapolated that the effect would remain consistenteven if a child went from drinking none to one a day.
Only 7 percent of the children did not change their soft drinkintake over the two years. Fifty-seven percent increased theirintake, with a quarter of them drinking two or more extra cans aday, the study said.
Soft drinks tracked in the study included regular sodas,Hawaiian Punch, lemonade, Kool-Aid, sweetened iced tea or othersugared fruit drinks. Pure fruit juice intake was also tracked, butthat did not account for the effect, the study said.
"The odds of becoming obese increased significantly for eachadditional daily serving of sugar-sweetened drink," the studyconcluded.
An increase in diet soda consumption made the children lesslikely to become obese.
Dr. Philip James, chairman of the International Obesity TaskForce, an independent worldwide scientific organization which wasnot connected with the study, said the evidence so far indicatesthat sugar is slightly less fattening than fat, but that sugar indrinks can be deceptive because the beverages are less filling thanfood.
He said one explanation might be that while people tend to eatless at a meal if they have overeaten at a previous sitting,evening out the calories, they don't tend to do that if the extracalories came from drinks. They tend to eat a normal-sized mealdespite having loaded up on sugar from soft drinks.
Kids’ Soft Drink Consumption Doubles
In the last 10 years, soft drink consumption has almost doubledamong children in the United States, Ludwig said, adding that theaverage American teenager consumes 15 to 20 extra teaspoons ofsugar a day just from soda and other sugared drinks.
Half of all Americans and most adolescents consume soft drinksdaily, and most of those are regular, not diet, the study said.
In a 1998 report on the issue, the U.S. health lobby groupCenter for Science in the Public Interest called soft drinks"liquid candy."
Childhood obesity has been linked to later development ofdiabetes, heart disease, cancer and arthritis.