Soda + sugar = obesity

Sugary drinksNew research points squarely at soda and other sugary drinks as culprits in the obesity epidemic.

A decades-long study, involving more than 33 000 Americans, has yielded the first clear proof that drinking sugary beverages interact with genes that affect weight, increasing the risk of obesity, beyond that caused by heredity. Conversely, two other major experiments found that giving children and teens calorie-free alternatives leads to less weight gain.

The first result strongly suggests that soda, juice and sport beverages sweetened with sugar cause people to pack on the kilogrammes, over and above healthy or unhealthy behaviour patterns, such as overeating and too little exercise. This could add weight to the push for taxes and other policies to curb sugars drinks. On the other hand: soda lovers can be reassured that sugar-free drinks did not raise the risk of obesity in these studies.

The studies were published online by the New England Journal of Medicine.

The research involved three long-running studies that separately and collectively reached the same conclusions that, having many inherited ‘fat’ genes will not guarantee that people will become obese, but if they drink a lot of sugary beverages, ‘they fulfil that fate’, comments Jules Hirsch of Rockefeller University in New York. ‘The sweet drinking and the fatness go together, and it’s more evident in genetic predisposition people.’

Sugary drinks are the single biggest source of calories in the American diet, and they are increasingly blamed for the fact that a third of US children and teens and more than two-thirds of adults are obese or overweight. Consumption of sweetened beverages and the obesity rate have risen in tandem — both have more than doubled since the 1970s in the US.

‘Until now, however, experiments have not conclusively shown that reducing sugary beverages would lower weight or body fat,’ says David Allison, a biostatistician at the University of Alabama at Birmingham. He believes the new studies on children changed his mind and convinced him that limiting sweet drinks can make a difference.

‘I know of no other single food product whose elimination can produce this degree of weight change,’ concurs the study’s leader, Dr David Ludwig of Boston Children’s Hospital and the Harvard School of Public Health.

According to Yale School of Medicine’s Dr Sonia Caprino’s report in the journal, the studies ‘provide strong impetus’ for policies urged by the Institute of Medicine, the American Heart Association and others to limit sugary drink consumption. However, the American Beverage Association disagrees.

‘Obesity is not uniquely caused by any single food or beverage,’ commented an Association’s spokesperson. ‘Studies and opinion pieces that focus solely on sugar-sweetened beverages, or any other single source of calories, do nothing meaningful to help address this serious issue.’