Tufts researchers recently reported that while the leading source of calories in the average American diet used to be from white bread, that may have changed. Now, according to preliminary research conducted by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Americans are drinking these calories instead. The research was presented in abstract form at the Experimental Biology Conference in April of this year and a more comprehensive paper is being developed.
A sharp report by Naila Moreira at the Science News Online site discusses how Bermudez' study fits in the context of other recent research, including an invited commentary by Robert Murray of the Ohio State University in the Journal of Pediatrics last month:
Odilia Bermudez, PhD, MPH, studied the reported diets of a large nationwide sample of American adults. Among respondents to the 1999-2000 National Health and Nutrition Examination Survey (NHANES), more than two thirds reported drinking enough soda and/or sweet drinks to provide them with a greater proportion of daily calories than any other food. In addition, obesity rates were higher among these sweet drink consumers. Consumers of 100% orange juice and low fat milk, on the other hand, tended to be less overweight, on average.
Bermudez, who is also an assistant professor at Tufts University’s Friedman School of Nutrition Science and Policy, is hopeful that, “by helping to identify the main sources of excess energy in the American diet, this work may contribute to the development of much-needed strategies to combat obesity in the American public.”
“These results are startling,” she continued, “and indicate that we need a much better understanding of how the American diet has changed.
Our paper will look more closely at the issue of sweet drink consumption and its relation to obesity factors among three of the main ethnic groups included in the national surveys: African Americans, Hispanics and non-Hispanic whites.”
Experimental Biology 2005, San Diego. Abstract # 839.5 Bermudez, O., "Consumption of sweet drinks among American adults from the NHANES 1999-2000.”
Moreira links to other sources, including Murray's commentary (.pdf), which appears to be online for free. Another good resource is the Institute of Medicine's project on preventing childhood obesity at the National Academies. Somebody should forward a folder of recent research to Drew Davis of the National Soft Drink Association, who said of the recent Commercial Alert petition about soda and junk food in schools: "They didn't provide any proof that a problem exists -- where's there proof of a problem?"
Dieters may not realize how sugary beverages affect them, because they focus on avoiding calorie-rich solid foods, says Robert Murray of Ohio State University. "Liquid calories like this, I think we tend to just ignore them," he says.
Although Bermudez' findings might startle consumers, Murray says he's "not overly surprised" by the new data. In the May Journal of Pediatrics, he and his colleagues reviewed existing studies on the impact of soft drinks on children's diets and obesity levels. The researchers found that U.S. children and teenagers consume, on average, about two cans of soda or fruit drink a day. And a quarter of all teens drink as many as four cans a day, each one containing about 150 calories.
"That's a lot of calories. That's 600 calories," Murray says. "That's like an additional meal." For a teenage girl, who should be eating around 1,800 calories a day, he adds, "that's a third of her daily energy requirement taken in the form of just one food, soft drinks."
A host of problems accompanies such excessive sweet-beverage consumption, Murray's team found. The more sodas and fruit drinks children drank, the more obese they tended to be. Soft drinks also displaced milk in children's diets, diminishing their intake of nutrients such as calcium, iron, folic acid, and zinc.