It’s not uncommon for people to overestimate the healthiness of their eating habits. This can be due to a number of factors, such as a lack of awareness of the nutritional content of the foods they are consuming, a lack of understanding of what constitutes a healthy diet, or a tendency to focus on only one aspect of their diet (such as avoiding certain foods or nutrients) while ignoring others.
According to preliminary research to be presented at the American Heart Association’s Scientific Sessions in 2022, most persons who were trying to lose weight overestimated how healthy their food was. The conference, which will be held both physically and online from November 5–7, 2022, in Chicago, is a major international forum for the discussion of the most recent findings in cardiovascular science.
“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,” said study author Jessica Cheng, Ph.D., 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, both in Boston.
This research was conducted while Dr. Cheng was a predoctoral fellow/Ph.D. candidate in the department of epidemiology at the University of Pittsburgh School of Public Health.
According to the Centers for Disease Control and Prevention, about half of individuals in the U.S. seek to lose weight each year, with the majority attempting to eat more fruits, vegetables, and salads. Healthy eating is essential for the heart and general health, and longevity.
Dietary guidance from the American Heart Association issued in 2021 advises adults to eat a variety of fruits and vegetables; opt for whole grains rather than refined grains; choose healthy protein sources; substitute nonfat and low-fat dairy products for full-fat versions; choose lean cuts of meat (for those who eat meat); use liquid plant oils instead of tropical oils and animal fats; choose minimally processed over ultra-processed foods; minimize foods and beverages with added sugar; choose foods with little or no added salt; and limit or avoid alcohol.
In the greater Pittsburgh, Pennsylvania, area, 116 adults between the ages of 35 and 58 who were attempting to reduce weight had their meals analyzed by researchers. Participants documented everything they consumed daily for a year using the Fitbit app after meeting one-on-one with a dietician to review their diet. They also used a Fitbit to monitor their physical activity and weighed themselves every day.
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.
Jessica Cheng
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. At each time point, participants were required to complete a 24-hour meal recall for two days. The HEI is a metric for determining how closely a dietary pattern adheres to the Dietary Guidelines for Americans published by the US government.
A possible score ranges from 0 to 100, with a higher number denoting a healthier diet. The score is determined by how frequently a person consumes certain dietary components such as sodium, lipids, carbohydrates, whole and refined grains, fruits, vegetables, meat, and seafood.
To get their perceived scores, participants self-scored the quality of their beginning and ending diets. Based on the HEI’s components, they received scores on a range from 0 to 100 as well. As they scored both their starting and ending diets at the conclusion of the study, the self-evaluation of their starting diet constituted a “look back.” Their perceived diet change was what caused the difference between their initial and final scores. A difference of 6 points or less between the researchers’ HEI score and the participant’s perceived score was considered “good agreement.”
Nearly one in four participants’ scores at the end of the study exhibited good agreement between their perceived diet score and the researcher’s assessment of their diet. The scores of the remaining 3 participants out of 4 were poorly correlated, and the majority of them reported a perceived score that was greater than the HEI score determined by the researchers. The average perceived score was 67.6, and the average HEI score was 56.4.
In judging the change in diet score over 12 months, only 1 in 10 participants had a good agreement between their self-assessed change compared to the change in the researchers’ HEI score.
Based on the researcher-assessed score, participants improved their diet quality by roughly one point at the conclusion of the trial. Participants’ perceptions of their own self-worth improved by 18 points, nevertheless.
“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,” said Cheng. She suggests providing concrete information on what areas of their diet can be improved and how to go about making healthy sustainable nutrition changes.
“Future studies should examine the effects of helping people close the gap between their perceptions and objective diet quality measurements,” she said.
“Overestimating the perceived healthiness of food intake could lead to weight gain, frustrations over not meeting personal weight loss goals or lower likelihood of adopting healthier eating habits,” said Deepika Laddu, Ph.D., an assistant professor in the College of Applied Health Sciences at the University of Illinois, Chicago, and chair of the American Heart Association’s Council on Lifestyle Behavioral Change for Improving Health Factors.
“While misperception of diet intake is common among dieters, these findings provide additional support for behavioral counselling interventions that include more frequent contacts with health care professionals, such as dieticians or health coaches, to address the gaps in perception and support long-lasting, realistic healthy eating behaviors.”
The majority of participants were female (79%) and most identified as Caucasian (84%), which are limitations of the study that may prevent the generalization of the results to other populations.
Additionally, the researchers at the conclusion of the trial only evaluated assessments of diet quality. Questions like whether perception got more realistic throughout the course of the study or whether a person’s view of their diet aids or prevents them from making dietary adjustments may have been answered with the use of assessments made during the trial.
Co-authors are Tina Costacou, Ph.D.; Susan M. Sereika, Ph.D.; Bonny Rockette-Wagner, Ph.D.; Andrea M. Kriska, Ph.D.; Mary Lou Klem, Ph.D., M.L.I.S.; Margaret B. Conroy, M.D., M.P.H.; Bambang Parmanto, Ph.D.; and Lora E. Burke, Ph.D., M.P.H. Authors’ disclosures are listed in the abstract.
National Heart, Lung, and Blood Institute, a division of the National Institutes of Health, funded the study.
