Study finds most adults seeking to lose weight overestimate the healthiness of their diet

By Pooja Toshniwal PahariaNov 2 2022Reviewed by Danielle Ellis, B.Sc.

A recent study soon to be presented at the American Heart Association (AHA) Scientific Sessions 2022*, researchers evaluated the dietary patterns of adults seeking weight loss and residing in the greater Pittsburgh city of Pennsylvania.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources

Background

A large proportion of United States (US) adults try to reduce their body weight every year, with attempts to increase the consumption of salads, fruits, and vegetables. Healthy dietary patterns are critical for general and cardiovascular health and to improve survival.

Diet advice from the AHA (American Heart Association) published in the year 2021 included the following advice: consume various vegetables and fruits; whole grains instead of refined grains; opt for healthy sources of proteins; replace full-fat milk products with low-fat and non-fat versions; prefer meat with lean cuts (for meat eaters); replace animal fat and tropical oils by liquid-form plant oils; opt for minimally processed foods rather than ultra-processed ones; consume a minimal amount of sugar-containing food and beverages; eat foods with no or little added salt and avoid or restrict alcohol consumption.

About the study

In the present study, researchers assessed the dietary intake of adult weight loss-seeking Pittsburgh residents.

The study comprised 116 individuals aged between 35 and 58 years who met dieticians individually to discuss their diets, following which they tracked all solid and liquid food items consumed daily for a year using the Fitbit application. In addition, they weighed themselves daily and tracked their PA (physical activity) levels using wearable Fitbit devices.

For all participants, HEI (healthy eating index) scores were calculated at the commencement and termination of the analysis on the basis of the self-reported food items consumed to assess the alignment of their dietary patterns with the Dietary Guidelines for American individuals published by the US government. Higher HEI scores denoted healthier dietary habits.

Twenty-four-hour food record data of all individuals for two days at each time interval were analyzed. Diet qualities at the commencement and termination of the analysis were self-scored by the participants. The differences between the starting and terminal scores were considered the perceived dietary change. A ≤6.0-point difference between the HEI scores calculated by the researchers and the perceived scores determined by the participants was considered to be in good agreement.

Results

The average age of the study participants was 52 years, and most participants (79%) were women and Whites (84%). Participants who were changing their dietary habits for weight reduction showed a tendency to overestimate the healthiness of their diets. Additionally, self-perceptions of dietary improvements over 12 months were often inaccurate since the perceived scores did not match the HEI scores concerning improvements in diet quality. At the termination of the analysis, the HEI scores and self-perceived scores of 25% (one out of four) of study participants were in good agreement (score differences ranging between -45 points and 30 points).

The mean values for the perceived scores and HEI scores were 68 and 56, respectively. In judging dietary score changes over one year, a good agreement was observed for only 10% (n=1) of the study participants between the changes in the self-perceived scores compared to that in the HEI scores. At the termination of the analysis, the HEI scores showed a one-point improvement in the diet quality of the individuals, whereas the participants perceived that diet quality improved by 18 points.

The study author, Jessica Cheng, Ph.D., a postdoctoral research fellow in general internal medicine at Massachusetts General Hospital and in epidemiology at the Harvard T. H. Chan School of Public Health, Boston said, “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.”

Conclusions

Overall, the study findings showed that weight loss-seeking adult Pittsburgh residents overestimated the healthiness of their dietary patterns. According to Deepika Laddu, Ph.D., Assistant professor at the University of Illinois’s College of Applied Health Sciences, Chicago, and chair of AHA’s Lifestyle Behavioral Change for Improving Health Factors Council, an overestimation of the healthiness of dietary intake as perceived by individuals may lead to increased body weight, frustration due to the inability to meet personal weight reduction goals and make individuals less likely to adopt healthy dietary habits.

Future studies with equal sex and ethnicity representation must focus on dietary perceptions versus reality to improve dietary patterns. The findings underpin the need for more frequent counseling interventions by HCPs such as health coaches, nutritionists, and dieticians to address the gaps between perceptions and objectively measured nutritional improvements and strengthen long-term healthy eating habits.

This news article was a review of a preliminary scientific report that had not undergone peer-review at the time of publication. Since its initial publication, the scientific report has now been peer reviewed and accepted for publication in a Scientific Journal. Links to the preliminary and peer-reviewed reports are available in the Sources section at the bottom of this article. View Sources