As Americans have watched their collective waistline expand and public health deteriorate over the years, nutritionists have consistently pointed to an increasing reliance on calories from processed foods jammed with sugar, salt, and fat as a main culprit behind the obesity epidemic. On the diet front, the Most Wanted are candy, sugary drinks, and fast food, with cities and nutritionists pushing for measures such as soda taxes, restrictions on the construction of new fast-food restaurants, and the elimination of candy and junk food from schools. But by singling out individual items, are we going about combating obesity all wrong?
A new study from Cornell University’s Food and Brand Lab says these products do indeed get a bad rap from being implicated in America’s obesity epidemic—but that it might not be deserved. In an analysis of data collected from 5,000 Americans in the 2007 and 2008 National Household and Nutrition Examination Survey, researchers looked for an epidemiological relationship between the consumption of junk food and sugary drinks and a respondent’s weight. The results will surprise many: After excluding the clinically underweight and morbidly obese from the study, researchers found that for 95 percent of the population, consuming more soda, candy, and fast food is not associated with weight gain or a higher body mass index.
The analysis, conducted by professors David Just and Brian Wansink and published in the journal Obesity Science and Practice, does not claim that Big Gulps and bags of burgers are nutritious choices—only that these items are not the main culprits behind obesity.
“Simply put, just because those things can lead you to get fat doesn’t mean that’s what is making us fat,” Just told the Cornell Chronicle. “By targeting just these vilified foods, we are creating policies that are not just highly ineffective but may be self-defeating, as it distracts from the real underlying causes of obesity.”
The report suggests that instead of people depriving themselves of a favorite foods, which “can lead to frustration and ultimately have little impact on overall weight,” we should instead be monitoring overall calorie consumption from meals and snacking, as well as curbing our consumption of added fats from things like salad dressings, oils, sour cream, and bread. For public health advocates, the approach for curbing obesity, the report suggests, should also include the promotion of more exercise and consumption of nutritious foods such as fruits and vegetables.
The problem is that encouraging a proper balance of calorie intake and physical activity already is the approach of doctors and public health practitioners, according to leading nutritionist Marion Nestle of New York University. She agrees that “of course no one food is responsible” for obesity—but she won’t adopt the authors’ position that certain foods have been unfair targets for public health advocates.
“People who eat a lot of junk food and drink a lot of sodas have worse diets and take in more calories than those who don’t,” she said. “From my standpoint, cutting out junk food—i.e., sources of excessive calories—is a first step, and a good one for many people.”
There are also prior studies—some of which relied on the same data set as the Cornell research—that did find a correlation between junk food intake and weight gain. For instance, a 2013 CDC analysis of the National Health and Nutrition Examination Survey data from 2007–10 found that, on average, Americans consumed 11.3 percent of their daily calories from fast food, and that consumption was indeed higher among overweight and obese respondents than those with a normal weight. Another study of Michigan adults and their eating habits found that “the prevalence of obesity increased consistently with frequenting fast food restaurants.”
Soda has been found to contribute to weight gain in children as young as five. A 2013 study completed by researchers at the University of Virginia and published in the journal Pediatrics reported that five-year-old children who drank beverages sweetened by sugar every day were a staggering 43 percent more likely to be obese than those who drank the beverages less frequently or not at all.
Even if specific junk foods by themselves are not “the root cause” of the obesity epidemic—which could impact 40 percent of the U.S. population by 2050—the Cornell researchers acknowledge that the empty calories from these foods do contribute to the weight gain and manifold health ailments from which so many Americans suffer. Which is to say, this new report isn’t exactly a hall pass to add a daily doughnut or burger to your daily diet.
