November 17, 2015

Cornell Study Finds Common Food Culprits to Correlate Little With Obesity

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Fast food, soda and candy have long been key targets in the battle against obesity. However, researchers at the Food and Brand Lab recently found that junk food consumption might not be the prime cause of the current obesity rate in the United States, which is about 34.9 percent for adults, according to the Centers for Disease Control and Prevention.

Prof. David Just

Prof. David Just

The study, led by Prof. Brian Wansink and Prof. David Just, applied economics and management, looked at national data of the consumption frequency of candy, soda and fast food based on body mass index (BMI). For 95 percent of the population, there was no correlation between consumption of these foods and BMI.

“If we look at people who are heavier versus people who are lighter, there really doesn’t seem to be a big difference in how they’re going about eating these foods,” Just said.

The exception to this is morbidly obese or extremely underweight individuals, according to Just. While their consumption habits do correlate with their BMI, these individuals only account for a small percentage of the population.

The study was motivated by the increasing public focus on targeting these foods to tackle obesity. Earlier this year, Berkeley, California passed a cent-per-ounce tax on sodas and several states have additional sales taxes on non-diet soft drinks. In January 2014, Mexico began imposing a tax on sugary soft drinks, citing concern for public health as its reason.

“We went in and tried to figure out what this relationship is, expecting there to be some mild relationship,” Just said. “We were just sort of shocked to see a flat line.”

Instead, the study pointed to increased overall calorie consumption by Americans — an average of 500 calories more per day compared to forty years ago — as a more likely culprit for obesity.

According to an infographic published by Just and Wansink, rather than depriving yourself of favorite foods, obesity can be combated by monitoring overall calorie consumption and remaining especially conscious of foods that contain unnecessary amounts of fat or flour.

“Be conscious of intake of added fats like salad dressing, cooking oils, cream, and sour cream and things containing lots of flour such as cereal, breads and baked goods as these are the foods that Americans are eating more of,” the graphic says.

The results from this study may have substantial implications in public health, including the notion that junk food and soda should not be the main focus of policymakers.

“We need to be thinking broader. We can’t just narrowly focus on a few problem foods and think that that’s going to wipe out the obesity problem in the U.S.,” Just said. “We need awareness that fast foods and soda are not good for us, but I think we start to shoot ourselves in the foot a bit if we push for a soda policy and say this is going to change people’s lives when it’s probably not.”

The real culprits likely stem from the lack of consumption of healthy foods, like fruits and vegetables and may be found by determining what type of foods people consume most. However, further research is needed to investigate the cause, Just said.

In striving to uncover a link between junk food and obesity, the study also uncovers some hidden bias toward food. According to Just, certain foods have been targeted because it is “easy and obvious, and not necessarily because it is really the problem.”

“It’s part of a broader effort to look at what sorts of biases we tend to have not only in terms of what sorts of foods we choose to eat or choose not to eat, but also the biases we have when we approach a subject as a researcher,” Just said. “It looks at what sorts of biases we come with and how that impacts what sorts of questions we ask and how we interpret the data.”

The study will be published  in a forthcoming issue of Obesity Science and Practice.