Drinking the occasional sugar-sweetened beverage, be it soda, an energy drink, sweetened water, or fruit punch, isn’t going to make you fat. But it’s now clear that many children and adults are at risk for gaining weight if they consume too much of these products.
I want to share new research from three recent papers in the New England Journal of Medicine (NEJM) because, together, they provide some of the most compelling evidence of the role of sugary drinks in childhood obesity, which affects nearly one-fifth of young people between the ages of 6 and 19.
In the first study , researchers randomly assigned 641 normal-weight school children between the ages of 4 and 12 to one of two groups. The first group received an 8 oz sugary drink each day; the second received the artificially sweetened version. After 18 months, it was clear that the kids consuming the sugary drink had gained about 2.25 pounds more weight, compared with the kids drinking the zero calorie drinks. They also packed on more fat.
The second study  focused on 224 overweight and obese adolescents, who consumed up to two sugary drinks every day, yielded a similar result. Here, the intervention group received a delivery of bottled water and diet drinks to discourage sugary beverages in the home, which is where most of these products are consumed. The control group simply continued on the same path. After one year, teenagers in the sugar-free intervention group gained less weight. This was particularly true with Hispanic teenagers.
The third study  was a little different but provides an interesting example of how your genes interact with the environment—in this case, the drinks you imbibe. Here, the researchers used obesity risk variants in 32 genes to calculate an “obesity risk score” for the approximately 200,000 people in their study. The research team showed that if two people consume one or more sugar-loaded drinks each day, the one with the higher genetic risk score is more likely to put on the pounds. This is a sobering example of the old saying that “genetics loads the gun, but environment pulls the trigger.”
It may soon be possible to calculate your own obesity risk based on the genes you carry, enabling you to consider adjusting your diet accordingly. This personalized approach is just one feature of a rapidly evolving science called nutrigenomics. Yes, this is another one of those “omics” fields, there are lots of them popping up!
The NEJM findings support New York City’s courageous but controversial move to ban supersized drinks, and the American Medical Association’s proposal to impose a “soda tax” to discourage consumption. Tough strategies have worked for tobacco, and many would argue that similar steps are needed for sugary soda, because for some groups in the U.S. these beverages account for 15% of their daily calories. Adolescent boys, for example, down about 357 calories worth of these drinks each day, and sugar-sweetened beverages are the largest source of calories for children between 2 and 18 years old. Plus there’s evidence that drinking these beverages doesn’t suppress the appetite, so these may truly be just extra, empty calories.
It’s no secret that obesity has reached epic and epidemic proportions in the US; two thirds of adults and one third of children are obese or overweight. (See: A VIEW OF THE U.S. OBESITY EPIDEMIC). And, the consequences go well beyond appearance. Obesity raises the risk of type 2 diabetes, heart disease, fatty liver disease, and some cancers—the list goes on. If we don’t come to grips with this growing epidemic, this may be the first time in U.S. history where children will have a shorter life expectancy than their parents.
Americans spend more than $60 billion on weight loss schemes and products each year. These recent papers suggest that one strategy that might help us all is to cut out these sugary drinks (and, sadly, most fruit juices aren’t much better)—these beverages don’t curb your appetite and only add calories. This decision just might be the easiest, not to mention cheapest, part of any plan to achieve and maintain a healthy weight.
 A trial of sugar-free or sugar-sweetened beverages and body weight in children.
de Ruyter JC, et al. N Engl J Med. 2012 Oct 11;367(15):1397-406.
 A randomized trial of sugar-sweetened beverages and adolescent body weight.
Ebbeling CB, et al. N Engl J Med. 2012 Oct 11;367(15):1407-16.
 Sugar-sweetened beverages and genetic risk of obesity.
Qi Q, et al. N Engl J Med. 2012 Oct 11;367(15):1387-96.