When you’re trying to lose weight, any number of factors can weaken your resolve and get in the way of progress. But in many cases, the scale may refuse to budge, even if you’ve been sticking to your plan. Findings from a study show that part of the problem may lie in our dietary perceptions and misperceptions.
Researchers found that people trying to lose weight often overestimated how healthy their diet was, a gap that could sabotage weight-loss efforts. The preliminary research will be presented at the American Heart Association’s Scientific Sessions 2022, held in person in Chicago and virtually, November 5 to 7.
“We found that while people generally know that fruits and vegetables are healthy, there may be a disconnect between what researchers and healthcare professionals consider to be a healthy and balanced diet compared with what the public thinks is a healthy and balanced diet,” said 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, both in Boston, in a press release.
About Half of Adults in the U.S. Try to Lose Weight Each Year
Nearly half of U.S. adults try to lose weight each year, according to the Centers for Disease Control and Prevention (CDC) (PDF), with a majority attempting to eat more fruits, vegetables, and salads.
That’s an area that most Americans need to improve upon. A CDC report (PDF) published in January 2022 found that only about 1 in 8 adults consume the recommended 1.5 to 2 cups of fruit each day, and only 1 in 10 eat the recommended 2 to 3 cups daily of vegetables, including legumes.
Most People Don’t Realize How Much Tweaking Their Diet Can Use
To find out how people’s perceptions of their eating habits matched up with reality, researchers recruited 116 adults ages 35 to 58 years old in the Pittsburgh area who were trying to lose weight.
Study participants met one-on-one with a dietitian to discuss their nutrition and then tracked what they ate and drank every day for one year on the Fitbit app. They also weighed themselves daily and wore a Fitbit device to track their physical activity.
Researchers evaluated the diets of the participants at the beginning and end of the study and gave each person a Healthy Eating Index (HEI) score based on the types of foods that participants reported eating.
The HEI is a measure for assessing how closely a dietary pattern aligns with the U.S. government’s Dietary Guidelines for Americans. A score of 0 to 100 is assigned, based on the frequency of eating various dietary components such as fruits, vegetables, whole and refined grains, meat and seafood, sodium, fats and sugars The higher the score, the healthier the diet.
Participants were also asked to complete a 24-hour food recall for two days at each time point.
When the one-year trial was over, the subjects used the HEI to score themselves on the quality of their diet. The self-assessment of their beginning diet was a “look back” as they scored both their starting and ending diets at the end of the study; the difference in their starting and ending score was their perceived diet change. A difference of 6 points or less between the researchers’ HEI score and the participant’s perceived score was considered “good agreement.”
Investigators found that 3 out of 4 participants’ scores had poor agreement, meaning that the overall health of their diet didn’t align with the experts’ assessments. In most cases, subjects perceived score was higher than the HEI score assigned by researchers- the average perceived score was 67.6, and the average HEI score was 56.4.
In judging the change in their diet over the course of the 12-month study, only 1 in 10 participants correctly estimated how much they had improved their eating habits. On average, participants improved their diet quality by only about 1 point based on the researcher-assessed score. However, participants’ self-estimate was 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,” said Dr. Cheng.
Some Limitations to the Study’s Findings
The authors acknowledged some limitations to the findings. The participants were mostly female (79 percent) and the majority reported white race (84 percent), so the findings may not apply in the same ways to other populations.
It’s also worth noting that the researchers only assessed diet quality perceptions at the end of the study. Assessments throughout the study may have helped to answer questions such as whether perception became more realistic over the course of the study or whether a person’s perception of their diet helps or hinders them from making dietary changes, said the authors.
A Lack of Awareness About the Healthiness of Foods Could Lead to Weight Gain
“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, PhD, an assistant professor in the College of Applied Health Sciences at the University of Illinois in Chicago, and chair of the AHA’s Council on Lifestyle Behavioral Change for Improving Health Factors, in the press release.
While it’s not uncommon for dieters to overestimate the health of the foods they eat, these findings provide additional support for behavioral counseling interventions that include more frequent contacts with healthcare professionals, such as dietitians or health coaches, to address the gaps in perception and support long-lasting, realistic healthy eating behaviors, said Dr. Laddu.
Food Choices Linked to 2 out of 3 Heart Disease-Related Deaths
Healthy eating is essential for heart and general health, and longevity, according to the AHA. Heart disease is the leading cause of death in both men and women in the United States, causing an estimated 659,000 deaths each year, according to the CDC.
More than two-thirds of heart disease-related deaths worldwide can be linked to food choices, according to a study published in October 2020 in the European Heart Journal Quality Care Clinical Outcomes. Study authors estimated that six million deaths could have been avoided through better diets.
Recommendations on Where to Find Reliable Information About the Nutritional Content of Different Foods
Dietary guidance from the AHA issued in 2021 advises offers the following recommendations for adults:
- Eat a variety of fruits and vegetables
- Choose whole grains over refined grains
- Choose healthy protein sources
- Substitute nonfat and low-fat dairy products for full-fat versions
- If you eat meat, choose lean cuts
- 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
- Limit or avoid alcohol
Educating yourself about the nutritional content of different foods is a good idea, but beware of misinformation on the internet, says Alice H. Lichtenstein, DSc, chair of the writing group for the AHA statement and senior scientist and director of cardiovascular nutrition team at the USDA Human Nutrition Research Center on Aging at Tufts University in Boston.
Dr. Lichtenstein recommends getting information from reputable sources like government websites like the FDA or the National Institute of Health (NIH). “Advocacy organizations such as the AHA or the American Diabetes Association will have sound dietary advice as well,” she says.
She also recommends checking the internet to find nutritional information for takeout or prepared meals. As a general rule, even for prepared foods or takeout foods, the less processed the better, according to Lichtenstein.
If you read something about a certain food or diet that seems “too good to be true” it probably is, she says. When in doubt about embarking on a type of diet, talk to your healthcare provider, she added.
Eating Healthier Doesn’t Have to Be ‘All or Nothing’
When it comes to developing a healthy eating pattern, it’s important to understand that it doesn’t have to be “all or nothing, to experience the benefits,” says Susan Strom, RD, at UNC Health in Chapel Hill, North Carolina, who was not involved in the research.
“Take a look at your typical intake and decide you want to change one thing and go from there,” she suggests. “Maybe it’s to stop drinking soda or to make sure you eat at least one fruit and one vegetable every day or start cooking dinner at home more versus getting takeout.”
The important thing is to make changes you can stick with long term in order to make them stick, she says. “Keep adding in new goals for yourself with regards to foods and activity in order to not only improve the quantity of your life, but the quality of your life as well.”
