idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
Researchers at the Max Planck Institute for Human Development have critically examined the basis for a frequently cited figure: that people make more than 200 unconscious decisions about food every day. This figure has circulated in scientific publications, the media, and health promotion campaigns for nearly 20 years without ever being empirically validated. An article published in the journal Appetite shows why a more nuanced view of eating behavior is needed.
Numbers play a central role in health communication, providing guidance and motivation. However, the benchmarks used are not always scientifically sound or meaningful. In health research, the claim that people make more than 200 decisions about food every day without even noticing has been around for years. "This number paints a distorted picture of how people make decisions about their food intake and how much control they have over it," says Maria Almudena Claassen, postdoctoral fellow at the Center for Adaptive Rationality at the Max Planck Institute for Human Development. Together with Director Ralph Hertwig and Jutta Mata, an associate research scientist at the Max Planck Institute for Human Development and Professor for Health Psychology at the University of Mannheim, Claassen has published an article that shows how flawed measurements can lead to misleading ideas about eating behavior.
Where the figure of 200 food decisions per day comes from
The figure of 200 food decisions examined in the article comes from a 2007 study by U.S. scientists Brian Wansink* and Jeffery Sobal. They asked 154 participants to first estimate how many decisions they made per day about eating and drinking—an average of 14.4. Next, participants estimated the number of "when," "what," "how much," "where," and "with whom" decisions they made for a typical meal. These estimations were multiplied by the number of meals, snacks, and beverages they reported consuming in a typical day and summed, giving an average of 226.7 decisions made per day. The authors interpreted the difference of 212.3 between the two estimates as an indicator of unconscious or "mindless" decisions.
Why this number is problematic
Claassen and her colleagues at the Max Planck Institute for Human Development challenge this conclusion. They identify methodological and conceptual shortcomings inherent in the study’s design and argue that the discrepancy in the estimated number of decisions can be explained by a well-known cognitive effect called the subadditivity effect. This effect describes people's tendency to provide higher frequency estimates when asked to assess several specific aspects of a general question separately. The researchers conclude that the high number of "mindless" food decisions is not an empirically observed reality but rather the result of the subadditivity effect.
The research team also warns of the consequences that such simplistic statements can have on our understanding of eating behavior. "Such a perception can undermine feelings of self-efficacy," says Claassen. "Simplified messages like this distract from the fact that people are perfectly capable of making conscious and informed food decisions."
Why a methodological pluralism in researching food decisions is needed
So how can decisions about food be meaningfully defined and empirically investigated? The researchers propose defining food-related decisions in concrete, context-specific terms. What is being eaten? How much? What is being avoided? When? In what social or emotional context? These decisions can only be understood within the context in which they are made. They are based on specific, concrete situations—such as choosing between salad and pasta, or deciding whether to skip a serving. What matters most is focusing on the key decisions that align with one's personal goals: for someone aiming to lose weight, it might be opting for a light salad over pasta at dinner; for someone striving to eat more sustainably, it could mean choosing a vegetarian meal instead of a meat-based one.
To empirically map this perspective, the researchers advocate methodological pluralism, combining qualitative observations, digital tracking tools, diary studies, and cross-cultural research to gain a differentiated and realistic picture of people's everyday food decisions.
"Magic numbers such as the alleged 200 food decisions do not tell us much about the psychology of eating decisions, even more so if these numbers turn out to be themselves distorted," says Ralph Hertwig, Director at the Max Planck Institute for Human Development. "To get a better understanding of eating behavior, we need to get a better grasp of how exactly decisions are made and what influences them.”
Self-nudging can strengthen informed, health-promoting decisions
Armed with this knowledge and understanding of their food choices, people are in a better position to adopt healthy eating habits in their everyday lives. One useful strategy for everyday use is self-nudging. It involves designing one's environment so that healthier choices are easier to make. For example, placing pre-cut pieces of fruit within easy reach in the refrigerator or keeping sweets out of sight can help people stick to their goals without constantly having to rely on conscious control. Self-nudging is part of the boosting approach, which, unlike nudging, strengthens individual decision-making competences rather than relying on external environment-driven cues (Reijula & Hertwig, 2022).
In brief:
• For years, the idea that people make over 200 unconscious food choices per day has been widely circulated. However, this figure is based on a methodologically problematic study and paints a distorted picture of human decision-making.
• Such simplistic statements can undermine people's feelings of self-efficacy and falsely suggest that their food decisions are beyond their conscious control.
• Researchers at the MPI advocate methodological pluralism in studying food decisions
• Strategies such as self-nudging can strengthen informed, health-promoting decisions.
Footnote:
* While Brian Wansink was removed from his academic position and had 18 of his articles retracted, the study discussed here has not been retracted. Our critique focuses not on misconduct but on methodological and conceptual shortcomings inherent in the study’s design.
Claassen, M. A., Mata, J., & Hertwig, R. (2025). The (mis-)measurement of food decisions. Appetite, 209, Article 107928. https://doi.org/10.1016/j.appet.2025.107928
The preprint is publicly available: Claassen, M. A., Mata, J., & Hertwig, R. (2025, July 4). The (mis-)measurement of food decisions. Retrieved from https://osf.io/preprints/psyarxiv/df2wr_v2
Reijula, S., & Hertwig, R. (2022). Self-nudging and the citizen choice architect. Behavioural Public Policy, 6(1), 119–149. https://doi.org/10.1017/bpp.2020.5
Link to the study of Brian Wansink* and Jeffery Sobal: https://journals.sagepub.com/doi/10.1177/0013916506295573
https://www.mpib-berlin.mpg.de/press-releases/myth-food-decisions Link to the press release on the MPIB website
Do we really make more than 200 food decisions per day? Such simplistic statements can undermine peo ...
Copyright: MPI for Human Development
Criteria of this press release:
Journalists
Nutrition / healthcare / nursing, Psychology, Social studies
transregional, national
Research results
English
Do we really make more than 200 food decisions per day? Such simplistic statements can undermine peo ...
Copyright: MPI for Human Development
You can combine search terms with and, or and/or not, e.g. Philo not logy.
You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).
Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.
You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).
If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).
