Think You Eat Healthily? 75% Of People Are Too Optimistic

How do people rate the quality of their diet and are they accurate?

How do people rate the quality of their diet and are they accurate?

Most people overrate their diet quality and sometimes they believe what they eat is very healthy, despite the reverse being true.

When American adults were asked about how healthy their diet was, three-quarters were too optimistic, a study reveals.

Dr Jessica Thomson, the study’s first author, said:

“We found that only a small percentage of U.S. adults can accurately assess the healthfulness of their diet, and interestingly, it’s mostly those who perceive their diet as poor who are able to accurately assess their diet.

Additionally, most adults overrate the quality of their diet, sometimes to a substantial degree.”

The research team wanted to know if a simple but effective question could be introduced as an assessment tool to complement or replace the food frequency questionnaires in nutritional studies.

Self-rated health is a single question like “how would you rate your general health? Excellent, very good, good, fair, or poor?”.

It is well known that self-rated health is a good predictor of diseases, illnesses and death.

But it is not clear if self-rated diet could foresee how good people’s diet is.

85% were incorrect

The team analysed data from 9,700 American adults in the National Health and Nutrition Examination Survey.

They found that 85 percent of participants scored their diet quality incorrectly.

About 75 percent considered their diet healthier than it was and 63 percent rated their diet quality as “very good”.

Only 15 percent of adults were accurate — surprisingly it was those who had rated their diet quality as “poor”.

Women, adults with lower income, and those with lower education were more likely to value their diet quality correctly.

Dr Thomson said:

“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.

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.”


  • What you eat has a bigger impact on your health than any powerful drug.
  • The Green Med diet leads to more weight loss and improves heart health.
  • People fed a healthier diet from an early age have a higher IQ.
  • Women’s mental health is more sensitive to what they eat than men’s.

The study was published in the American Journal of Health Promotion (Thomson et al., 2022).

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