Three studies published in this week’s New England Journal of Medicine suggest that drinking sugar-sweetened beverages contributes to obesity, lending weight to the theory that capping sugary drink consumption – as New York City did this month – could help curb the American obesity epidemic. One in three adults and approximately 17 percent of children in the United States are now obese, according to the Centers for Disease Control and Prevention. The connection between sugary drinks and obesity has long been suspected, as research has shown that sugary drink consumption rose at the same rate as obesity prevalence over the last 30 years, with both doubling since the late 1970s. These latest studies examine the direct effect of sugary beverage consumption on test subjects, and all find that the drink contributes to obesity. Two of the studies were randomized experiments that compared weight gain among young people who drank sugary drinks and those who drank sugar-free drinks. In one of these trials – conducted at the University of Amsterdam – 641 children were given either a sugary or sugar-free version of the same drink – formulated to be indistinguishable in taste – for a year and a half. Researchers found that “the sugar-free group gained significantly less body fat” over that time. And while the sugar-free group gained approximately 14 pounds on average over 18 months, the sugar group gained an average of about 16.24 pounds over that time. The other randomized trial – funded by the National Institutes of Health and conducted in Boston – followed 224 overweight or obese adolescents who regularly consumed sugary drinks. Half of the participants were instructed to drink noncaloric beverages and water, which were delivered to their homes, over the course of a year, while the other group continued with regular consumption habits. At the end of the year, Body Mass Index (BMI) was found to be significantly higher among those who had continued to drink sugary drinks. After a second year in which no instructions were given, however, no significant difference was found between the BMIs of the two groups, although the group that had switched to sugar-free drinks the previous year showed a lower sugar intake in the second year. The third study – conducted at the Harvard School of Public Health – analyzed three cohorts of over 33,000 men and women of European ancestry and found that among people who are genetically predisposed to obesity, greater consumption of sugary beverages leads to a higher BMI. “Increased consumption (of sugar-sweetened drinks) might contribute to the obesity epidemic by interacting with a genetic predisposition to elevated BMI,” write the authors. The beverage industry argued that the results of these studies do not point to a need to regulate sugary drink consumption. “Obesity is a serious and complex public health issue facing our nation and the rest of the world, and we all must work together to solve it,” said the American Beverage Association in a statement Friday. “We know, and science supports, that obesity is not uniquely caused by any single food or beverage. Thus, 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.” ABA points out that caloric intake from sugar-sweetened beverages declined by more than 20 percent between 2001 and 2010 while obesity continued to rise, and that sugar-sweetened drinks account for only 7 percent of calories in the average American’s diet. Consumer advocates said these study results highlight a clear need for legislation limiting sugary drink consumption. “Considering the enormous personal and economic costs of obesity, it’s high time for concerted action at all levels of government to reduce consumption of sugary drinks,” said Michael F. Jacobson, Executive Director of the health advocacy group Center for Science in the Public Interest in a statement Friday. “We can start with major education campaigns, requiring warning notices on labels, imposing substantial taxes on sodas, and eliminating soda from public buildings and parks. “Nutritionally worthless sugary drinks are the largest single source of calories in the American diet,” said Jacobson. “Consumers who want to reduce their risk of becoming a statistic in the next round of studies linking soda to weight gain and obesity would be well advised to sharply reduce or eliminate their consumption.” And so the debate over whether or not to regulate soft drink consumption continues, but with a one-two-three punch from science now on the pro side. Two weeks ago, New York City’s Board of Health approved a measure to limit sugary drink serving sizes to 16 ounces in movie theaters and restaurants amid a storm of controversy. The beverage industry claimed that singling out one food will not affect obesity, while many consumers balked at the idea of a “nanny state” that would tell people what they can and can’t eat. Health groups and doctors have called on the U.S. Surgeon General to issue a report on sugary beverages, saying that since these drinks have been linked to obesity and related diseases such as heart disease, cancer and diabetes, they require the same attention as cigarettes, which became highly regulated in the late 1990s after scientific evidence linked smoking to cancer.