Moderate smartphone use of three hours a day significantly increases the risk of teens becoming overweight or obese, a study warns.
Researchers from Korea University looked for links between smartphone use, obesity and health-related behavior in some 53,000 adolescents.
They found that even sitting online on a device for two hours a day was linked to unhealthy habits such as eating more junk food and fewer fruits and vegetables.
The team said screen time could pave the way for obesity through pathways such as disrupted sleep, exposure to food marketing and “brainless” eating while online.
Child obesity rates are increasing in many countries, including the United Kingdom, United States and South Korea.
Overweight or obese teens are more likely to be obese as adults, increasing the risk of health complications, including diabetes and heart disease.
Even moderate smartphone use of three hours a day significantly increases the risk of teens becoming overweight or obese, a study warns (stock image)
POSSIBLE REASONS WHY SMARTPHONES CAN CAUSE OBESITY
Professor Oh said there were a number of drivers that could explain their findings, including:
- Smartphone use leads to insufficient sleep,
- Teens get more exposure to online food ads,
- Screens take up time that would have been spent on exercise,
- An increased tendency to eat ‘mindless’ and use a device at the same time.
More work will be needed to establish the importance of these factors.
“Previous studies have shown that TV viewing is an important factor that increases the risk of obesity in children and adolescents,” said author and epidemiologist Hannah Oh of Korea University in Seoul.
However, she added, “Little is known about the effects of modern screen time, such as smartphone use, on diet and obesity.”
“Our data suggest that both smartphone usage time and content type may independently influence diet and obesity in adolescents.”
In their study, Professor Oh and colleagues analyzed data from more than 53,000 adolescents — each aged 12-18 — collected by the Nationally Representative Korea Youth Risk Behavior Web-based Survey.
The team compared respondents’ smartphone use to the extent to which they engaged in both healthy habits such as eating fruits and vegetables and unhealthy behaviors such as skipping breakfast or consuming fast food and junk food.
The team also took into account variables such as socioeconomic status that are known to influence obesity rates as well as smartphone ownership.
The team found that teens who spent more time on their smartphones were more likely to exhibit unhealthy behaviors as well as become overweight or obese.
Compared to teens who had two hours or less of screen time each day, those who spent five or more hours on their smartphones each day ate significantly more chips, fast food, and instant noodles.
These adolescents also drank sugary drinks more often than those who spent less time on their phones.
The team compared respondents’ smartphone use to the extent to which they engaged in both healthy habits such as eating fruits and vegetables and unhealthy behaviors such as skipping breakfast or consuming fast food and junk food, as shown.
The way adolescents use their phones was also found to have an influence.
Teens who reported using their devices more for searching and retrieving information tended to have healthier habits than those whose screen time was primarily spent messaging, gaming, accessing music/videos, or browsing social media.
And those who primarily used their phones for gaming, music/video or reading web-based cartoons or novels were more likely to be overweight or obese, the team said.
To explain the findings, Professor Oh suggested that phone use could lead to insufficient sleep, increase exposure to online food ads, decrease time that would otherwise be spent on physical activity and increase “mindless” eating.
The researchers added that online food marketing aimed at teens should be monitored and, if necessary, regulated, while smartphones, on the other hand, could be used to promote public health through, for example, food-tracking apps.
Teens who reported using their devices more for information search and retrieval (shown here in light gray) tended to have healthier habits than those whose screen time was primarily spent on messaging (orange), gaming (dark gray), accessing music/videos (yellow) or social media browsing (light blue)
“Adolescents today are digital natives, who grew up in close contact with digital devices such as smartphones and so are likely to be heavily influenced by them,” the researchers said.
“Efforts should be made to maximize the positive effects and minimize the negative effects of smartphone use on adolescent health.”
The team cautioned that their study was unable to determine whether the temporal relationship between obesity and screen time would be — and that a long-term study would be needed to see how device use affects body weight over time.
The full findings of the current study will be presented at the Nutrition 2021 Live Online conference, which will be held virtually this year from June 7 to 10.
HOW SERIOUS IS SMARTPHONE ADDICTION?
With the average age at which a child gets their first phone is only 10 years old, young people are becoming increasingly dependent on their smartphone.
Worrying research from Korea University suggests that this reliance on the technology may even affect the brains of some teens.
The findings show that teens who are addicted to their smartphones are more likely to experience mental health disorders, including depression and anxiety.
Other studies have shown that people are so dependent on their smartphones that they like to break social etiquette to use them.
Researchers from iPass, a mobile connectivity company, surveyed more than 1,700 people in the US and Europe about their connectivity habits, preferences and expectations.
The survey revealed some of the most inappropriate situations in which people have felt the need to check their phones — during sex (seven percent), on the toilet (72 percent) and even at a funeral (11 percent).
Nearly two-thirds of people said they felt anxious when not connected to Wi-Fi, and many said they would give up a range of items and activities in exchange for a connection.
Sixty-one percent of respondents said Wi-Fi was impossible to give up — more than for sex (58 percent), junk food (42 percent), smoking (41 percent), alcohol (33 percent), or drugs (31 percent).
A quarter of respondents went so far as to say they would prefer Wi-Fi over a bath or shower, and 19 percent said they would prefer Wi-Fi over human contact.