You Probably Aren’t Eating As Healthy as You Think

A new study shows that American adults often overestimate the quality of their diet.

Is your diet healthy? It seems like an easy question, but according to recent research, it’s one that most Americans fail to answer correctly.

“We found that only a small percentage of American adults can accurately assess the healthfulness of their diet, and interestingly, it is mostly those who perceive their diet to be poor who can accurately assess their diet,” said Jessica Thomson, Ph. .D. , research epidemiologist at US Department of Agriculture Agricultural Research Service in the Southeast Area, lead author of the study. “Furthermore, most adults overestimate the quality of their diet, sometimes to a considerable degree.”

Thomson presented the findings at NUTRITION 2022 LIVE ONLINE, the premier annual meeting of the American Society for Nutrition held June 14-16.

Investigator-assessed average diet quality (100 being the highest possible score) among groups of participants who accurately rated their diet quality. For participants who accurately rated the healthiness of their diet, diet quality scores increased as participants’ perception of diet increased from poor to excellent for overall diet quality (Total Healthy Eating Index). [HEI] score) and for the dietary components of vegetables, fruits, sodium, and added sugars. However, the same increasing pattern was not present for the dairy component of the diet. Credit: Dr. Jessica Thomson, Research Epidemiologist, USDA Agricultural Research Service

The aim of the study was to determine whether a single direct question can serve as a substitute or addition to comprehensive dietary questionnaires that are often used in nutrition research as a screening tool for nutrition studies. Self-rated health has been shown to be a reliable indicator of morbidity and death in previous studies, but little is known about the relationship between self-rated diet quality and actual diet quality.

The National Health and Nutrition Examination Survey, a biannual survey of people in the United States that is nationally representative, provided the data for the research. Participants were required to complete completed 24-hour food recall forms and rate their diet as excellent, very good, good, fair, or poor.

The researchers rated the quality of each participant’s diet using meal recall questionnaires. Fruits and vegetables, whole grains, healthy fats, reduced-fat dairy products, seafood, and plant proteins are some examples of foods that qualify as healthier. Refined grains and foods high in salt, added sugars or saturated fat were among the foods considered less nutritious.

For participants who incorrectly assessed the healthiness of their diet, diet quality scores were generally higher in the poor perception group compared to the other four total diet quality perception groups (Healthy Eating Index total). [HEI] score) and for the fruit, sodium, and added sugar components of the diet. The same pattern was not present for the vegetable and dairy components of the diet. Credit: Dr. Jessica Thomson, Research Epidemiologist, USDA Agricultural Research Service

The study revealed significant disconnects between the scores calculated by the researcher and how the participants rated their own diet. Of more than 9,700 participants, about 8,000 (approximately 85%) incorrectly assessed the quality of their diet. Of these, almost all (99%) overestimated the healthiness of their diet.

Surprisingly,[{” attribute=””>accuracy was highest among those who rated their diet as poor, among whom the researcher’s score matched the participant’s rating 97% of the time. The proportion of participants who accurately assessed their diet quality ranged from 1%-18% in the other four rating categories.

Thomson said further research could help to elucidate what factors people consider when asked to assess their diet quality. For instance, it would be helpful to know whether people are aware of particular dietary recommendations and whether they take into consideration where their food is purchased or how it is prepared.

“It’s difficult for us to say whether U.S. adults lack an accurate understanding of the components of a healthful versus unhealthful diet or whether adults perceive the healthfulness of their diet as they wish it to be—that is, higher in quality than it actually is,” said Thomson. “Until we have a better understanding of what individuals consider when assessing the healthfulness of their diet, it will be difficult to determine what knowledge and skills are necessary to improve self-assessment or perception of one’s diet quality.”

Meeting: NUTRITION 2022 LIVE ONLINE