Researchers say your willingness to overeat may be tied to how you see yourself.
For many people in the United States, Thanksgiving is the biggest meal of the year. But a few hours after you push back from the table, do you eat a smaller dinner or overindulge again? The answer, it seems, may be related to how you see yourself.
“We had participants eat a large lunch that was 60 percent of their daily requirements
– 60 percent of the energy we calculated their body would need to get through the
day,” said study co-author Emily Dhurandhar, an assistant professor in the Department of Kinesiology & Sport Management in the College of Arts & Sciences. “Then we let them eat whatever they wanted outside the lab at home. So, if they
wanted to – and were consciously or physiologically aware of how much energy their
body needs – they had the free choice and the opportunity to compensate for the big
meal by eating less later on.
“We found that someone's subjective social status – their perception of where they are in the social hierarchy – is associated with their ability to compensate for these meals. Those with low social status tended to take in more energy than they burned under these feeding conditions.”
In collaboration with John Dawson, an assistant professor in the Texas Tech Department of Nutritional Sciences, within the College of Human Sciences, and the Center for Biotechnology & Genomics, Kinesiology & Sport Management researchers Nadeeja N. Wijayatunga, Bridget Ironuma, Bailey Rusinovich and Dhurandhar used the MacArthur Scale of Subjective Social Status to measure participants' perceived social status. This scale is commonly represented by a ladder: at the top of the ladder are the people who are the best off – those who have the most money, the most education and the most-respected jobs – while the people who are the worst off are at the bottom of the ladder, those with the least money, the least education and the least-respected jobs or no job at all.
“It asks people to rate where they are based on their job, their amount of money and their education level,” Dhurandhar said. “The higher up you are, the closer you are to the people at the very top, and the lower you are, the closer you are to the people at the very bottom.”
Those who reported the lowest perceived social status ate more after their large lunch, whereas those with higher perceived social status ate fewer calories.
Interestingly, eating behaviors were not affected by any traditional measures such as income or education. Perceived social status, Dhurandhar noted, is more important than actual social status for one very important reason.
“You might have all the money in the world, but if you don't perceive that it's enough, that still will impact your behaviors,” she said.
While the image of someone overeating to deal with feelings of inadequacy is nothing new in popular culture, the roots of these behaviors reach far back into human history.
“It all comes down to the basic principles of survival,” Dhurandhar said. “There's a possibility that body fat is insurance against starvation. It's the idea that if, for any reason, you perceive your food supply might be threatened, it's possible you would have a tendency to gain fat as insurance in case your access to food is threatened in the future.”
And it's not just a human trait.
“We see this with certain types of birds,” Dhurandhar said. “If you expose them to food-insecure conditions, those who are high on the social ladder don't really seem to change their intake in response, but those who are low on the social hierarchy will spend more time foraging and more time eating, and they will gain excess fat.”
It's important to note that participants' greater energy consumption during the two-week pilot study did not translate to measurable weight gain, so the study doesn't prove that lower perceived social status causes overeating, nor does it prove that lower perceived social status is associated with weight gain. But it does show an association between perceived social status and the overeating that eventually could result in weight gain.
“This is a model of who's a poor compensator,” Dhurandhar said. “If you eat a big meal, we wanted to understand what predicts who will adjust well for that meal and hopefully maintain their weight, and who doesn't and might be prone to weight gain. It seems we might be having some excess energy intake and some eating behaviors that could lead to weight gain, but we need to do a larger, longer-duration study so we can really confirm this.”
This pilot study's greatest potential, Dhurandhar said, comes in its ability to change how nutrition researchers view the causes of obesity. For years now, they have been studying the role of food deserts – areas, especially those with low-income residents, with limited access to affordable and nutritious food.
“Obviously, obesity is associated with low social status in developed countries,” she said. “It's tempting and intuitive to say that's because those lower-income populations don't have access to resources for physical activity or they don't have access to fruits and vegetables.
“But I think this new research and other research studies suggest it's also possible that it's not that social status creates conditions where the person is prone to weight gain, but social status causes the behaviors that lead to weight gain.”