The myth of 200 daily food decisions
How a methodological bias has shaped perceptions of eating behavior—and why more sophisticated measurement approaches are needed
Max Planck Institute for Human Development
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Do we really make more than 200 food decisions per day? Such simplistic statements can undermine people's feelings of self-efficacy.
view moreCredit: MPI for Human Development
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 Wansink1 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:
1 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.
Original publications:
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 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
What counts as a food decision? Food decisions only make sense when you know the context in which they were made.
Credit
Pietro Nickl
Journal
Appetite
Method of Research
Commentary/editorial
Subject of Research
People
Article Title
The (mis-)measurement of food decisions
Study finds Mediterranean or plant-based diets may help reduce risk of chronic constipation in middle- and older-age adults
Mass General Brigham
The incidence of chronic constipation increases as we age. A new study from Mass General Brigham researchers compares five common diets to determine the effectiveness of preventing chronic constipation in middle- and older-age adults. The team studied over 96,000 adults for several years to understand how different eating habits affect the risk of developing the chronic gastrointestinal condition. They found people who followed a Mediterranean or plant-based diet were less likely to develop constipation. Their results are published in Gastroenterology.
“Chronic constipation affects millions of people and can significantly impact a patient’s quality of life,” said senior author Kyle Staller, MD, MPH, of the Division of Gastroenterology at Massachusetts General Hospital, a founding member of the Mass General Brigham healthcare system. “Our findings suggest that as we age, certain healthy diets may provide benefits to our gut beyond the known cardiovascular benefits.”
It’s been established that healthy diets can improve constipation symptoms, but this is the first study to show that certain diets can prevent people from developing chronic constipation. “We have always assumed that the benefits of eating a healthy diet would be driven by fiber, but our analyses showed the benefit of these healthy diets on constipation were independent of fiber intake,” said Staller.
Using data from the Nurses’ Health Study, Nurses’ Health Study II and the Health Professionals Follow-Up Study, the researchers tracked dietary patterns in middle- and older-age adults and examined who developed chronic constipation, which was defined as having symptoms for at least 12 weeks in a year. Diets included in the analysis were the Mediterranean diet, plant-based diet, low-carb diet, Western diet and inflammatory diet. Individuals who adhered to a Western or inflammatory diet were more likely to develop chronic constipation. In addition, participants who ate a low-carb diet didn’t show a strong effect.
“Our findings suggest a diet rich in vegetables, nuts and healthy fats may help prevent chronic constipation in middle- and older-age adults,” said Staller.
Authorship: In addition to Staller, Mass General Brigham authors include Braden Kuo, Madeline Berschback and Andrew T. Chan.
Disclosures: Andrew T. Chan served as a consultant for Pfizer Inc., and Boehringer Ingelheim. Kyle Staller has received research funding from Ardelyx and ReStalsis and has served as a consultant to Ardelyx, Gemelli Biotech, Laborie, Mahana, ReStalsis, Salix, and Takeda. Braden Kuo has been a consultant to Ironwood, Takeda, Atmo, Restalsis, Pahthom. No other disclosures were reported.
Funding: This work was supported by the National Institutes of Health (U01 CA167552, UM1 CA186107, P01 CA87969, U01 CA176726, K23DK120945).
Paper cited: Wang Y., et. al. “Dietary Patterns and Incident Chronic Constipation in Three Prospective Cohorts of Middle- and Older-aged Adults” Gastroenterology. DOI: 10.1053/j.gastro.2025.06.020
About Mass General Brigham
Mass General Brigham is an integrated academic health care system, uniting great minds to solve the hardest problems in medicine for our communities and the world. Mass General Brigham connects a full continuum of care across a system of academic medical centers, community and specialty hospitals, a health insurance plan, physician networks, community health centers, home care, and long-term care services. Mass General Brigham is a nonprofit organization committed to patient care, research, teaching, and service to the community. In addition, Mass General Brigham is one of the nation’s leading biomedical research organizations with several Harvard Medical School teaching hospitals. For more information, please visit massgeneralbrigham.org.
Journal
Gastroenterology
Method of Research
Observational study
Subject of Research
People
Article Title
Dietary Patterns and Incident Chronic Constipation in Three Prospective Cohorts of Middle- and Older-aged Adults
Article Publication Date
2-Jul-2025
COI Statement
Andrew T. Chan served as a consultant for Pfizer Inc., and Boehringer Ingelheim. Kyle Staller has received research funding from Ardelyx and ReStalsis and has served as a consultant to Ardelyx, Gemelli Biotech, Laborie, Mahana, ReStalsis, Salix, and Takeda. Braden Kuo has been a consultant to Ironwood, Takeda, Atmo, Restalsis, Pahthom. No other disclosures were reported.
Late eating is associated with impaired glucose metabolism
Our metabolic processes differ depending on the time of day and many of them are more active in the morning than in the evening. Although studies show that eating late in the day is associated with an increased risk of obesity and cardiovascular diseases, little is known about how the time when we eat affects glucose metabolism and to what extent this is genetically defined. Prof. Olga Ramich from the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE) and her team recently investigated this in a twin cohort. The article was published in the journal eBioMedicine.
The circadian system is a hierarchically structured 24-hour time control system in the body that regulates behavior and metabolism via a central clock in the brain and peripheral clocks in organs such as the liver or pancreas. As a result, our metabolic processes differ depending on the time when we eat, which leads to diurnal fluctuations in glucose metabolism and the release of hormones after a meal. Food intake itself acts as an important timer that synchronizes our internal clocks. Decoupling meal times from the natural light-dark rhythm, e.g. when working at night, can lead to an internal clock disorder and negative metabolic changes.
Does late eating make you ill?
Previous studies have shown that eating late at night is associated with an increased risk of obesity and cardiovascular diseases.
However, little is known about how exactly the timing of food intake interacts with the individual circadian rhythm and thus influences glucose metabolism and the risk of diabetes. It is also unclear which mechanisms determine one’s individual eating behavior, as it depends on the interaction of cultural, personal, physiological and genetic factors.
Background information
Circadian Timing of Eating
When someone eats during the course of a day in relation to the individual biological daily rhythm is measured as the interval between mealtime and the midpoint of sleep. The midpoint of sleep describes the time that lies exactly in the middle between falling asleep and waking up. It is a measure of the chronotype – in other words, whether someone is an early riser or a night owl.
NUtriGenomics Analysis in Twins (NUGAT) Study
The NUGAT study, initiated and designed by Prof. Andreas F. H. Pfeiffer, was conducted from 2009 to 2010 at the German Institute of Human Nutrition Potsdam-Rehbrücke (DIfE). The identical and fraternal twin pairs were recruited either from a twin register (HealthTwiSt, Berlin, Germany) or via public advertisements. The 92 participants (46 pairs of twins) underwent two nutritional interventions, which were not relevant to the study results shown here though.
The participants underwent detailed metabolic phenotyping, which included a physical examination, medical history, anthropometric measurements and a glucose tolerance test. The individual chronotype was determined by means of a questionnaire. In addition, all 92 test subjects filled out handwritten food logs in which they noted the start and end of each meal as well as the amount and type of food consumed on five consecutive days. This included three working days and two days off to reflect the eating habits of the twin pairs.
Journal
EBioMedicine
Article Title
Later eating timing in relation to an individual internal clock is associated with lower insulin sensitivity and affected by genetic factors.
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