Moderate smartphone use of three hours a day significantly increases the risk that teenagers will become overweight or obese, a study has warned.
Researchers from the Korea University looked for associations between smartphone usage, overweight and health-related behaviours among some 53,000 adolescents.
They found that even spending two hours per day online on a device was linked to unhealthy habits like eating more junk food and less fruits and vegetables.
The team said that screen time may pave the way to obesity through such routes as disrupted sleep, exposure to food marketing and ‘mindless’ eating while online.
Rates of childhood obesity are increasing in many countries, including in the United Kingdom, the United States and South Korea.
Teenagers who are overweight or obese 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 that teenagers will become overweight or obese, a study has warned (stock image)
POSSIBLE REASONS WHY SMARTPHONES MAY LEAD TO OBESITY
Professor Oh said that there were a number of drivers that might explain their findings, including:
- Smartphone use leading to inadequate sleep,
- Teens getting increased exposure to online food adverts,
- Screens taking up time that would have been spend on exercise,
- An increased propensity to engage in ‘mindless’ eating at the same time as using a device.
More work will be needed, to establish the importance of these factors.
‘Earlier studies have shown that TV watching is an important factor that increases the risk of obesity in children and adolescents,’ said paper author and epidemiologist Hannah Oh of the 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 analysed data on more than 53,000 adolescents — each aged 12–18 years — that was collected by the nationally representative Korea Youth Risk Behaviour Web-Based Survey.
The team compared the respondents’ smartphone usage with the extent to which they engaged in both healthy habits like eating fruit and vegetables, as well as unhealthy behaviours such as skipping breakfast or consuming fast and junk food.
The team also accounted for variables like socioeconomic status that are known to influence both obesity rates and smartphone ownership.
The team found that teens who spent more time on their smartphones were more likely to both engage in unhealthy behaviours and become overweight or obese.
Compared with teens who had two hours or less of screen time each day, those spending five or more hours on their smartphones daily were significantly more likely to eat chips, fast food and instant noodles.
These adolescents were also more likely to drink sugary beverages than those who spent less time on their phones.
The team compared the respondents’ smartphone usage with the extent to which they engaged in both healthy habits like eating fruit and vegetables, as well as unhealthy behaviours such as skipping breakfast or consuming fast and junk food, as pictured
The way that adolescents use their phones was also seen to have an impact.
Teens who reported using their devices more for information search and retrieval had healthier habits overall than those whose screen time was primarily spent sending messages, 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.
Looking to explain the findings, Professor Oh suggested that phone use may lead to inadequate sleep, increase exposure to online food adverts, subtract from time that might otherwise be spent on physical activity and increase ‘mindless’ eating.
The researchers added that online food marketing aimed at teens needs to be monitored and, if necessary, regulated — while, on the flip side, smartphones could be used to promote public health via, for example, nutrition tracking apps.
Teens who reported using their devices more for information search and retrieval (shown here in light grey) had healthier habits overall than those whose screen time was primarily spent sending messages (orange), gaming (dark grey), accessing music/videos (yellow) or browsing social media (light blue)
‘Adolescents of today are digital natives, who have grown up in close contact with digital devices such as smartphones and thus are likely to be heavily influenced by them,’ the researchers said.
‘Efforts should be taken to maximize the positive effects and minimize the negative effects of smartphone use on adolescent health.’
The team cautioned that their investigation was not capable or determining the temporal relationship between obesity and screen time — and that a long-term study would be needed to see how device usage affects body weight over time.
The full findings of the present study will be presented at the Nutrition 2021 Live Online conference, which is being held virtually this year from June 7–10.
HOW SEVERE IS SMARTPHONE ADDICTION?
With the average age for a child to get their first phone now just 10, young people are becoming more and more reliant on their smartphones.
Worrying research from Korea University suggests that this dependence on the technology could even be affecting some teens’ brains.
The findings reveals that teenagers who are addicted to their smartphones are more likely to suffer from mental disorders, including depression and anxiety.
Other studies have shown people are so dependent on their smartphone that they happily break social etiquette to use them.
Researchers from mobile connectivity firm iPass 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 phone – during sex (seven per cent), on the toilet (72 per cent) and even during a funeral (11 per cent).
Nearly two thirds of people said they felt anxious when not connected to the Wi-Fi, with many saying they’d give up a range of items and activities in exchange for a connection.
Sixty-one per cent of respondents said that Wi-Fi was impossible to give up – more than for sex (58 per cent), junk food (42 per cent), smoking (41 per cent), alcohol (33 per cent), or drugs (31 per cent).
A quarter of respondents even went so far as to say that they’d choose Wi-Fi over a bath or shower, and 19 per cent said they’d choose Wi-Fi over human contact.