TEENS TRAPPED IN A PERFECT STORM OF UNHEALTHY HABITS

Fast food, screens, and a lack of greens are sending teenage health into dangerous territory, according to new research from the University of South Australia.

A global study of more than 293,000 adolescents aged 12 to 17 across 73 countries has found that more than 92.5% of teenagers are engaging in two or more unhealthy lifestyle behaviours, significantly increasing their risk of developing chronic diseases like obesity, diabetes, and heart disease later in life.

The study, led by Dr Ming Li of UniSA, analysed habit clusters including physical activity, diet, screen time, and soft drink consumption. The findings were bleak:

• 85% of teens don’t get enough exercise

• 80% aren’t eating enough fruit and vegetables

• 50% regularly eat fast food

• 39% consume excessive sugary drinks

• 32% spend too much time on screens

  
  

“The teenage years are a critical window for growth and development – physically, mentally, and emotionally – and they set the foundation for long-term health,” said Dr Li.

“But with junk food so readily available, and physical activity often replaced by screen time, more teens are picking up multiple unhealthy habits that could lead to serious health issues down the track.”

While Australian teens weren’t specifically assessed, Dr Li noted their behaviours would likely mirror trends in other high-income countries, where 13% of teens reported all five major unhealthy behaviours.

The study also showed just how rare healthy lifestyles are: only 0.5% of teens globally reported no unhealthy behaviours at all.

Regional patterns revealed that teenagers in higher-income countries – including the Americas and Eastern Mediterranean – are more likely to stack up unhealthy habits.

Factors such as urbanisation, sedentary school environments, and limited access to fresh food and green space are contributing to the crisis, particularly in low- and middle-income regions.

But the study also found protective factors that reduce risk. Supportive families, peer groups, and food security were all linked with healthier lifestyle choices:

• Supportive families: 16% reduction in high-risk behaviours

• Supportive peer groups: 4% reduction

• Food-secure households: 9% reduction

  
  

Dr Li called for urgent, systemic action.

“It’s clear we need systemic action – better school-based physical activity programs, urban design that gives teens access to green spaces, policies that make healthy food affordable, and limits on junk food marketing to children,” Dr Li said.

The findings come as the South Australian Government rolls out its ‘LiveLighter’ campaign to tackle obesity and promote healthier living across the State.