Obesity has become an increasingly serious problem around the world and it is regarded as one of the major risks to human health. Many factors such as more wealth and food accessibility may explain its prevalence. Now, there is a possible psychological explanation as well.
A recent research study by The Chinese University of Hong Kong (CUHK) Business School on "Mere Experience of Low Subjective Socioeconomic Status Stimulates Appetite and Food Intake", published in Proceedings of the National Academy of Sciences of the United States of America (PNAS), reveals that feelings of occupying lower socioeconomic status can make us consume more food, and fatty food, in particular.
The study was conducted by Ying-yi Hong, Choh-Ming Li Professor of Marketing at the Department of Marketing and Principal Investigator of Culture Lab at the CUHK Business School, together with her former post-doctorate fellow Bobby Cheon, now an assistant professor at Nanyang Technological University's School of Humanities and Social Sciences, Singapore.
According to the study, there has not been much attention paid to the impact of subjective socioeconomic status on people's obesity in the study of diet-related health. Unlike objective indicators of socioeconomic status, such as actual income, education or occupational status, subjective socioeconomic status is largely based on perceived relative possession of material and social resources compared with others.
"Even people with a decent job or wage could feel inferior if they are surrounded by people whom they see as richer and better off," says Prof. Hong.
According to Prof. Hong, there are no studies to date which have tested whether the mere psychological experience of low subjective socioeconomic status would stimulate appetite and calorie intakes. However, she believes that such subjective socioeconomic status may be sufficient to stimulate appetite and consumption of greater calories.
"When people are facing low socioeconomic status, they may feel deprived, which in turn make them take an adaptive response to seize and exploit other resources for survival. One of such resources is food," Prof. Hong explains.
For the purpose of the research, four experiments were carried out.
In the first study, 101 participants in Singapore were asked to think of a ladder as representing where people stand in Singapore. Then they were asked to compare themselves to the people at the very bottom/top of the ladder, who are the people having the least/most money, and with the least/most education and least/most respected jobs. Participants who compared themselves with people at the very bottom would experience a high subjective socioeconomic status (SSES), whereas those who compared with people at the very top would experience a low SSES.
Following the comparison, participants were asked to select what they would eat for their next meal from a hypothetical buffet. Calories of the food they selected were estimated. The results showed that the participants in the low SSES condition were more likely to pick high-calorie foods than did those in the high SSES condition.
"The result suggests that low socioeconomic status may increase people's motivation and intention to consume more foods, or food with higher calories," Prof. Hong says.
In the second study, using the same comparison of social status as in the first study, 167 people were tested on their "implicit" evaluation of both high-calorie foods, such as pizzas and burgers, and low-calorie foods, such as vegetables and fruits. The result again showed that participants in the low SSES condition, in comparison with those in the high SSES condition, were more likely to associate high-calorie with pleasant words, such as tasty, delicious, wonderful, rather than unpleasant words, such as disgusting, nasty and awful, indicating that they subconsciously preferred high-calorie foods.
"When people are facing low socioeconomic status, they may feel deprived, which in turn make them take an adaptive response to seize and exploit other resources for survival. One of such resources is food," Prof. Hong says.
To examine whether the experience of low socioeconomic condition stimulates actual food intake from snacks during a fixed time interval, a third study was performed. Similar with the first and second studies, the same experimental manipulation of socioeconomic status was conducted with 83 participants who then viewed a short documentary video while freely eating three snacks (potato chips, M&M candies, and California raisins). The result showed that participants in the low SSES condition consumed 65 per cent more calories than those in the high SSES condition.
"Feeling socioeconomically inferior not only changes the perception of food but can trigger your actual food intake," Prof. Hong points out.
In the last study, the research looked at whether low socioeconomic status would stimulate food intake when larger portions were provided in a meal. After comparing their socioeconomic status as before, 148 participants were each given a big bowl of noodles and asked to eat until they were comfortably full. Consistent with the previous experiments, participants who felt they were of a lower status consumed more, specifically, an average of 201 grams (or 20 per cent more) as compared with 169 grams of those who felt the opposite.
"Across four experiments, we found that participants who felt they're of low socioeconomic status subsequently exhibited greater automatic preferences for high-calorie foods, and also actually ate more," Prof. Hong comments.
Social status, she said, acts as 'a buffer or insurance' against pressure. Without the protection afforded by higher social status, people may switch to seek the protection offered by other available resources -- such as food.
All studies have demonstrated that the mere mindset or subjective feeling of lower socioeconomic status and standing when compared with others may contribute to obesity and metabolic disease independent of actual economic deprivation. As such, the study sheds light on potential interventions to curb the obesity pandemic.
"Given that simply feeling inferior to other people could be sufficient to alter our diets and healthy lifestyle, we believe certain measures could be taken to tackle the growing obesity and overweight problem in our society."
"Intervention focusing solely on reducing such material and financial barriers may not be sufficient to address the issue of obesity and diabetes in our society. Our result suggests that intervention should be focused on people's subjective experience of low socioeconomic status. For example, helping low status individuals to feel secured and empowered may buffer their sense of relative deprivation. At the societal level, we would need to fix the problem of social inequality, reducing the widening gap between the wealthy and the poor. Indeed, other research has shown that greater levels of income inequality were associated with higher rates of obesity, diabetes mortality rates, and daily calorie intake across wealthy nations. These findings together with mine underscore the importance of reducing social inequality as a way to curb the obesity pandemic," Prof. Hong remarks.
