Most Americans overestimate the health of their diet; the most accurate are those whose power supply is of poor quality

According to new research, you probably think your diet is healthier than it actually is.

Image credits Steve Buissinne.

One of the most enduring truisms about life might very well be that the better the food tastes, the worse it has to be for your health. Judging by the results of a new study, while Americans can judge the flavor of a certain dish very well, they aren’t as good at judging its healthiness.


“We found that only a small percentage of American adults can accurately rate the healthiness of their diet, and interestingly, it is primarily those who perceive their diet as unhealthy who are able to accurately rate their diet. “said Jessica Thomson, PhD, research epidemiologist. with the U.S. Department of Agriculture’s Agricultural Research Service Southeast Region, the study’s lead author.

“Furthermore, most adults overestimate the quality of their diet, sometimes to a substantial degree.”

The findings are based on data from the National Health and Nutrition Examination Survey, a nationally representative survey of American adults that is conducted every two years. Participants in this study were asked to detail their diet over the past 24 hours and to rate their diet through a series of questionnaires. Diets can be described as excellent, very good, good, fair or poor.

According to the authors, previous research has shown that self-reported diet quality is a good predictor of morbidity and mortality, but we don’t really have evidence to show whether self-reported dietary information is reliable or not. This lack of knowledge motivated the present study.

The purpose of the study was to determine if a single clear question could be used as a screening tool for further nutrition studies. Such a question can be used to supplement or even replace the more detailed, but also much longer dietary questionnaires currently used in nutrition research. The usefulness of such a single question, however, would hinge on the reliability of self-reported dietary data – so the team set out to test that.

Based on food recall questionnaires from the National Health and Nutrition Survey, the team assessed the dietary quality of each participant. Some of the items they ranked as healthier included fruits and vegetables, whole grains, healthy fats, low-fat dairy, seafood, and plant-based protein. Foods considered less healthy included refined grains, foods high in sodium, or those with high levels of added sugars or saturated fats.

According to the findings, there are significant discrepancies between the health scores calculated by the researchers and the participants’ own rankings. Of the 9,700 participants analyzed in this study, approximately 8,000 (85% of the total) provided an inaccurate assessment of the quality of their diet. Virtually all (99% of those 8,000) tended to rate their diet as healthier than the researchers had calculated.

A surprising finding was that participants who rated their diet as “poor” were the most accurate in their ratings. Their scores matched those of the searchers 97% of the time. For other categories, accurate ratings ranged from 1% to 18%.

The results show that self-reported diet quality data is most often unreliable, but it’s not yet clear why. More research is needed to determine which factors people turn to when asked to rate their diet. Thomson says it would be useful to know, for example, whether people are actually aware of healthy dietary recommendations and whether they consider the source and method of preparation of their food.

“It’s hard for us to say whether American adults don’t accurately understand the components of a healthy or unhealthy diet or whether adults perceive the healthiness of their diet as they want it to be, that is, better. quality than it actually is,” she adds. “Until we have a better understanding of what individuals consider when rating the safety of their diet, it will be difficult to determine what knowledge and skills are needed to improve self-report or perception the quality of his diet.

The results will be presented on Tuesday, June 14 during the NUTRITION 2022 LIVE ONLINE session Relationship Between Dietary Patterns and Behavioral/Societal Outcomes.

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