Adults Trying to Lose Weight May Overestimate How Healthy Their Diets Are

Many adults dieting to lose weight may overestimate how healthy their eating habits are, according to research presented at the American Heart Association’s (AHA) Scientific Sessions 2022.

“We found that while people generally know that fruits and vegetables are healthy, there may be a disconnect between what researchers and health care professionals consider to be a healthy and balanced diet compared to what the public thinks is a healthy and balanced diet,” study author Jessica Cheng, PhD, a postdoctoral research fellow in epidemiology at the Harvard T. H. Chan School of Public Health and in general internal medicine at Massachusetts General Hospital, said in a press release.

The AHA issued a dietary guidance in 2021 suggesting that adults consume a variety of fruits and vegetables, choose whole grains instead of refined grains, eat healthy protein sources and lean cuts of meat, and substitute nonfat and low-fat dairy products for full-fat versions, among other measures.

The investigators evaluated the diets of 116 adults between 35 and 58 years of age in the greater Pittsburgh, Pennsylvania area who were trying to lose weight. The participants had 1-on-1 meeting with a dietitian to discuss nutrition habits and tracked the daily food and beverages they consumed for 1 year on the Fitbit app. They also recorded their weight each day and tracked their physical activity.

The researchers calculated a Healthy Eating Index (HEI) score at the beginning and end of the study based on the types of foods that participants reported eating. Participants also completed a 24-hour food recall for 2 days at each time point.

The HEI assesses how closely a dietary pattern aligns with the US Dietary Guidelines for Americans. The score is calculated between 0 and 100, with a higher score indicating a healthier diet. The HEI records the frequency of consuming various dietary components, such as fruits, vegetables, whole and refined grains, meat and seafood, sodium, fats, and sugars.

The participants self-scored their beginning and ending dietary quality to evaluate their perceived scores, and which were on a 0-100 scale based on the sections of the HEI.

The difference in participants’ starting and ending score was their perceived diet change, and a difference of 6 points or less between the research team’s HEI score and the participant’s score was considered a “good agreement.”

By the end of the study, approximately 1 in 4 participant scores showed good agreement between perceived diet score and researcher-assessed score. The remaining 3 of 4 participant scores showed poor agreement, with most reporting a perceived score higher than the HEI score assigned by researchers. The average perceived score was 67.6, whereas the average HEI score was 56.4.

Only 1 in 10 participants had good agreement between their self-assessed change compared to the change in the researchers’ HEI score. The participants improved their diet score toward the end of the study by approximately 1 point based on the researcher-assessed score; however, the self-estimates showed a perceived 18-point improvement.

“People attempting to lose weight or health professionals who are helping people with weight loss or nutrition-related goals should be aware that there is likely more room for improvement in the diet than may be expected,” Cheng said in a press release.

She added that progress could be gained by providing more specific information for areas of improvement in participants’ diets and tips for making healthy and sustainable nutrition changes.

“Future studies should examine the effects of helping people close the gap between their perceptions and objective diet quality measurements,” Cheng said in the release.

Some study limitations included that the participants were mostly female (79%) and of white race (84%), which impacted the findings to vary by other populations. The researchers also assessed diet quality perceptions only at the end of the study, whereas assessments throughout may have helped to answer other questions the researchers had.

REFERENCE

Study finds dieters may overestimate the healthiness of their eating habits. American Heart Association. October 31, 2022. Accessed November 1, 2022. https://newsroom.heart.org/news/study-finds-dieters-may-overestimate-the-healthiness-of-their-eating-habits?preview=64cf