The new normal? Overweight teenagers likely to underestimate excess kilos, experts flag

03 Jul 2023 --- Teenagers in Europe and North America are increasingly underestimating their body weight, according to a team of international researchers. The study found that the actual body weight and its misperception is increasing, adding to the existing public health crisis of obesity, diabetes and overweight. 

Therefore, body weight perception (BWP) among the young needs more attention.

The study says that misleading BWP is common among teenagers. However, if BWP is underestimated – when the actual weight is higher than its perception – it sparks worries among the researchers.

“Strengthening BWP should be part of health literacy programs and interventions focused on maintaining a healthy body weight. However, it can be difficult to know what a healthy body weight is and knowledge shared by social media might not always be incorrect,” Dr. Anouk Geraets, lead author of the study and a researcher at the Department of Social Sciences at the University of Luxembourg, tells Nutrition Insight. 

“During this impressionable age, body weight perception may influence a young person’s lifestyle choices, such as the amount and types of food they eat and their exercise habits,” she notes. 

The WHO recently warned that obesity in the EU is at “epidemic proportions.” Meanwhile, half of the earth’s population will be overweight or obese by 2050 if current patterns are not changed, according to the World Obesity Federation. 

“It’s concerning that we’re seeing a trend where fewer adolescents perceive themselves as being overweight – as this could undermine ongoing efforts to tackle increasing levels of obesity in this age group,” says Geraets.

External factors such as social media may contribute to body weight perception.Social media and body image
Body image changes throughout times and trends, and Geraets says that the ’90s and ’00s were characterized by a thin body ideal for girls and a strong muscular body for boys. 

“In the ’90s and ’00s, girls and young women were exposed to a thin body ideal and were more likely to overestimate their body weight. Our data suggess that this overestimation has decreased and correct weight perception has increased among girls.”

“Over that time [1990-2010], girls were more likely to overestimate their body weight. As the overestimation decreased and underestimation increased, girls may have started comparing themselves to a strong muscular body ideal instead of the thin body ideal,” Geraets notes.

Therefore, external factors that contribute to body weight perception, especially from social media use, might be a causing factor.

“Adolescence is a sensitive period in life with important physical, mental and social changes. Adolescents often compare themselves to their peers and social media can have accelerated exposure to peers. Social media can have a positive and negative influence. Body positivity promoted via social media might have positively affected body weight perception.” 

Meanwhile, social media platforms such as TikTok have been shown to drive toxic diet cultures, and there is a lack of expert voices offering advice or reaching out to the young population.

Differences between borders
The data from nearly two decades (2002-2018) included 746,121 participants from 41 countries aged 11, 13 and 15, originating from the WHO and the Health Behavior in School-Aged Children (HBSC). 

The participants filled out their weight and height and BMI was used as a measurement for weight. The lead author stresses that BMI as a measure of healthy body weight can be criticized as many factors contribute to BMI besides food intake and physical activity, like DNA and medical conditions. 

“Though, it can still be a useful starting point. Schools can play an important role in this. Annual check-ups by GPs or school doctors can provide professional healthcare advice to all students. Schools can collect data about body weight and body weight perception and inform policymakers when they observe changes,” she adds.

They found that BWP differed among genders, and data from Australia, Thailand, China and the US showed that girls are more likely to overestimate their weight status than boys. Girls also reported having tried controlling their weight more than boys.

The study says there is limited evidence of gender differences in BWP, although normal-weight girls are less likely to perceive it correctly. However, there were gender and country differences in body weight perception and time trends.

“The athletic and strong body ideal may make adolescents want to increase their body weight, though this might not always be healthy,” she adds.

“Young people who underestimate their weight and, therefore, do not consider themselves overweight may not feel they need to lose excess weight and, as a result, they may make unhealthy lifestyle choices.”

Tackling perceptionBWP may influence a young person’s lifestyle choices, such as the amount and types of food they eat and their exercise habits.
The results of the study have clinical and public health implications. 

“The increase in correct weight perception and the decrease in overestimation may have a positive effect on unnecessary and unhealthy weight loss behaviors among adolescents, while the increase in underestimation might indicate the need for interventions to strengthen correct weight perception,” says Geraets.

“More research is now needed to understand the factors underlying these time trends and to develop effective public health interventions.” 

She adds that factors contributing to time trends in body weight perception on a national level are required, as well as policies and interventions to include elements necessary for a society to be effective. 

Geraets argues that policies and interventions that focus on maintaining a healthy body weight might not work if people don’t see themselves as being overweight. If unaware of the problem, they may not feel the need to lose the excess weight. 

Furthermore, she says that improving body weight perception in adolescents can positively affect body weight perception and maintain a healthy body weight in the future.

“Having a correct body weight perception is a major factor in maintaining a healthy body weight, though there are several social and commercial determinants of health that need to be tackled to enable teenagers to make healthy choices,” she concludes.

By Beatrice Wihlander