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Most dieting adults overestimate the healthiness of their food

Nearly half of adults in the US try to lose weight each year, according to the CDC.

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The average self-perceived score was 67.6, while the average score given by researchers was 56.4. (ESB Professional via Shutterstock)

By Alice Clifford via SWNS

Most adults trying to lose weight overestimate the healthiness of their diet which can actually lead to weight gain, suggests a new study.

The lack of awareness can also lead to mental issues as weight loss targets are missed and it can even put people off healthy food.

Dr. Deepika Laddu, of the University of Illinois in the US, 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.”

Nearly half of adults in the US try to lose weight each year, according to the Centres for Disease Control and Prevention, with a majority attempting to eat more fruits, vegetables and salads to knock off the pounds.

Researchers evaluated the diets of 116 adults aged between 35 and 58 in the greater Pittsburgh area, who were trying to lose weight.

Each participant spoke with a dietitian to discuss what they ate and then went on to track everything they ate and drank every day for one year via the Fitbit app.

They also weighed themselves daily and used a Fitbit to track how much they exercised.

The researchers worked out a Healthy Eating Index score at the beginning and end of the study based on the food each person ate.


This index is a way to see how closely someone’s diet aligns with the US government’s Dietary Guidelines for Americans.

A person was given a rating from 0-100, and the higher the score, the healthier their diet was. The difference between the start and end scores showed how their diet had changed over the year.

Each participant also scored themselves in the same way, so researchers could see how accurate people’s perception of their diet was.

A difference of six points or less between the researchers' score and their own personal score was considered a “good agreement."

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Overestimating the healthiness of your diet could lead to weight gain. (ESB Professional via Shutterstock)

By the end of the study, around one in four participants’ personal scores matched with the researchers’ score.

But the other 75 per cent of people did not match up with the researchers, with the majority of people giving themselves a higher score.

The average self-perceived score was 67.6, while the average score given by researchers was 56.4.

At the end of the study, participants improved their diet quality by about one point based on the researcher-assessed score. However, participants thought they had improved by 18 points.

Study author Dr Jessica Cheng, of Harvard T. H. Chan School of Public Health, 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.”

She added: “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.

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

The study does have some limitations. Out of all the participants, 79 per cent were female, 84 per cent were white and all of them were from Portland. With a more diverse group, the results could change.

Dr Laddu added: “While misperception of diet intake is common among dieters, these findings provide additional support for behavioural 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 behaviours.”

The findings will be presented at the American Heart Association Scientific Sessions due to be held in Chicago.

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