Conflict towards food improves portion size estimation

Video content:

Craving a bag of crisps or other guilty pleasure food, while knowing it’s unhealthy results in a better visual estimation of its portion size. Watch as Assistant Professor Nailya Ordabayeva of RSM, shows that the inner conflict between both desiring food and yet perceiving it as harmful, actually enhances consumers’ visual awareness of increases in food portion size.

As a result, children and adults who feel conflicted toward a certain food make a more accurate estimation of the actual amount the different food portions contain. Additionally, health claims on food packaging can reduce the inner conflict towards food and worsen portion perception.

“If people feel conflicted towards a certain food they're better at spotting and estimating portions.”

People rarely read the size information on food packaging labels, instead they rely on their visual impressions to estimate portion size. It has been suggested that people’s tendency to underestimate the size of today’s supersized portions is one of the drivers of the rise in the obesity epidemic. Ordabayeva’s study The Acuity of Vice: Attitude Ambivalence Improves Visual Sensitivity to Increasing Portion Sizes, co-authored with Professor Pierre Chandon and Yann Cornil of INSEAD, Ulrike Kaiser of the Research Institute of Child Nutrition Dortmund and Professor Bernd Weber of the University Hospital Bonn, shows that consumers’ inner conflict towards unhealthy foods, safeguards them against the underestimation of growing portion sizes and thus overeating.

Strikingly, the influence of conflict towards food on the estimation of portion size starts at a young age. As part of the study, a group of eight-year-olds were given the task to estimate portion size of either baby carrots or chocolate chunks. Researchers found that the inner conflict improved the size impressions of chocolate. Impressions of carrots were unaffected due to low levels of conflict associated with carrots in the first place.

Similar effects occur among people who feel naturally conflicted toward unhealthy foods. For example, dieters turn out to be better at estimating the sizes of unhealthy food products than non-dieters. However, not just intrinsic conflict can influence our visual perception. People can be induced to feel more or less conflicted towards food in the presence of external cues. Low-fat health claims on food packaging can reduce the feeling of conflict or guilt associated with unhealthy foods. This makes us feel less negatively about unhealthy foods and thus worsens our ability to keep track of changes in unhealthy food portions. Participants in one study were less accurate in the estimation of the portion size of crisps labeled as low-fat, in comparison to crisps that made no health claim at all.

Thesis abstract

The new study suggests that ambivalent attitudes toward food enhance visual sensitivity to changes in food portions. Supersized portions increase food intake partly because people rarely read the size information on the labels and instead rely on their visual impressions to estimate portion size. However, visual perception is biased, and consumers tend to underestimate the changes in food portions, more so for large portions than for small portions. As a result, consumers overeat because they fail to realize just how large supersized portions really are. These findings have brought the biases in portion size perception and their remedies to the forefront of the research and the policy agenda. Building on these findings, the authors predict that desiring a food item and perceiving it as harmful should enhance visual sensitivity to changing portions. Since in food decisions desire and harm perceptions reinforce each other, we expect that ambivalence (or conflict) between these two attitudes will influence impressions of food portions more than each attitude individually. Four studies demonstrate that this effect occurs when ambivalent attitudes are chronic, for example among restrained eaters, and when ambivalence is induced through external interventions, for example through ambivalence primes.

The findings contribute to the literature on motivated misperception by examining the interplay of wanting and liking in driving portion size perceptions. They also propose ambivalence as a useful tool for improving consumers’ portion size perceptions.

About the author

Nailya Ordabayeva is an Assistant Professor at Rotterdam School of Management, Erasmus University (RSM), with research interest in the field of transformative consumer research. Her research examines effects of wealth distributions on conspicuous and inconspicuous consumption, and perceptual and affective biases in consumer decision making. Ordabayeva 's research has been published in the Journal of Marketing, the Journal of Marketing Research and the Journal of Consumer Research, and it has received coverage in publications such as The New York Times, The Wall Street Journal, The Economist, and USA Today.

Rotterdam School of Management, Erasmus University (RSM) is ranked amongst Europe’s top 10 business schools for education and amongst the top three for research. RSM provides ground-breaking research and education furthering excellence in all aspects of management and is based in the international port city of Rotterdam - a vital nexus of business, logistics and trade. RSM’s primary focus is on developing business leaders with international careers who carry their innovative mindset into a sustainable future thanks to a first-class range of bachelor, master, MBA, PhD and executive programmes. RSM also has offices in the Amsterdam Zuidas business district and in Taipei, Taiwan.

Want to know more? Please contact Nailya Ordabayeva at For more information about RSM or on this release, please contact Ramses Singeling, Media Officer on +31 10 408 2028 or by email at


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