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Laptops, cell phones, tablets, and televisions are all growing thinner, but they may be causing adolescents to grow fatter. Child obesity rates are on the rise, and many precautions have been taken to combat it, such as elementary schools banning junk food or cafeterias serving healthier food options. However, these combatants have not reversed the rates of child obesity, which signals that the food may not be the only reason children are gaining excess weight.

With the increase of childhood obesity rates, researchers have ventured to study potential causes. Iranian researchers sought to find the root of the epidemic in adolescents and hypothesized a correlation between sedentary screen time and dietary habits. The study was conducted by researchers from several universities including Alborz University of Medical Sciences, Tehran University of Medical Sciences, Isfahan University of Medical Sciences, Jundishapu University of Medical Sciences, Maragheh University of Medical Sciences, Qom University of Medical Sciences, and Jahrom University of Medical Sciences.

The researchers designed a questionnaire which was distributed to 14,880 Iranian adolescents between the ages of six and eighteen. “The questions included the following items: individual information, family characteristics, and social and psychological environment of schools” (Kelishadi et al. 2017). The researchers also asked the adolescents about their physical activity levels at school and in general, allowing the researchers to calibrate the subjects and take into account of outside factors that might influence the study. Height and weight of the participants were recorded and used to calculate body mass index (BMI) prior to the study, providing researchers with a baseline variable to compare with their results.

In order to simplify the questionnaire, the researchers specified and categorized foods into nine categories: “sweets (cake, cookies, biscuits, and chocolate), salty snacks (puff, chips, and pretzel), soft drinks, fresh fruit, dried fruit, vegetables (fresh or cooked), canned fruit juice, milk, and fast food (sausage, pizza, and hamburger)” (Kelishadi et al. 2017). The subjects answered numerically the frequency of consumption of the nine categories. Researchers wanted to see how the food consumption was impacted by screen time, so they defined screen time as watching TV and using a computer and quantified it based on the hours spent on the device.

Of the 14,880 adolescents given the questionnaires, 13,486 participated in the study with equal numbers of males and females, with the majority living in urban areas. Once the data was recorded, the researchers analyzed the data and found a positive correlation between screen time and food consumption. This positive relationship means that increased screen time was likely followed by increased food intake. Thus indicating, screen time encourages mindless eating which over time could result in weight gain and even obesity in adolescents.

To further legitimize the study, the researchers compared their results to other studies. Results from other studies also indicated a positive relationship between screen time and food consumption. An American study, from 2015, found screen time usage was correlated with reduced intake of vegetables and fruits and increased intake in fast food and soft drinks (Lowry et al. 2015). Other studies from Europe, Canada, Norway, and Saudi Arabia affirmed the American study’s relationship between screen time and unhealthy eating. While some of the comparative studies found a negative relationship between screen time and intake of fruits and vegetables, the Iranian study did not indicate this conclusion. The researchers theorized the reason for this difference was because of the Iranian’s nutritional culture. Despite the slight differences, these correlations support the Iranian study because they indicated an increased intake of other food groups. In the Iranian study, researchers focused on the overall increase of food intake while using screens, including fruits and vegetables, rather than a decrease in one specific category. Another probable cause for the difference, researchers hypothesized, was due to advertisements for unhealthy foods on television which made adolescents more inclined to eat the advertised, unhealthy foods while using screens. While the results from the conclusion were widely verified, the researchers mentioned a few flaws that could potentially delegitimize the results.

One particular flaw present in the study was that the data was self-reported. This opened an entire Pandora’s box of issues such as social desirability bias, falsifying data, or misremembrance. Another issue was the nutrients of the foods were not included. Since the foods were only reported by the frequency of consumption of the nine categories, nutritional value of the foods could not be determined or taken into account. Other outside factors such as income, environmental circumstances, and maturity of the adolescents could have also impacted the results of the studies. The income of the families could have impacted the types of foods which were available to the participant. Environmental circumstances such as drought or poor harvest would also impact the availability of certain foods, particularly fruits and vegetables. And arguably, the most impactful factor, maturity, was not assessed. Maturity of the participants could influence the types of food eaten, the amount of food eaten, and the frequency of eating. Regardless of these uncertainties, the large pool of participants, and the alignment of the results with other studies means these flaws did not tamper the data too aggressively.

With these results in mind, it is important to remember that screens can often be accompanied with mindless consumption of food and if left unattended could result in obesity. If the obesity epidemic is not tended to, adolescents will suffer from other health deficits preventing them from reaching their full potential. While screens are part of daily life, it is important to educate children and adolescents on the negative effects of screen time on dietary health, so we can combat the obesity epidemic.



Kelishadi R, Mozafarian N, Qorbani M, Maracy MR, Motlagh ME, Safiri S, Ardalan G, Asayesh H, Rezaei F, Heshmat R. 2017 Feb 1. Association between screen time and snack consumption in children and adolescents: The CASPIAN-IV study. Journal of Pediatric Endocrinology and Metabolism. [accessed 2020 Feb 4]; 30(2): 211-219. doi10.1515/jpem-2016-0312.

Lowry R, Michael S, Demissie Z, Kann L, Galuska DA. 2015 May 25. Associations of Physical Activity and Sedentary Behaviors with Dietary Behaviors among US High School Students. J Obes. [accessed 2020 Feb 4]; 2015: 876524. doi: 10.1155/2015/876524.

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