This is the key finding from a new research paper, which says adolescent obesity goes largely untreated despite its huge impact later in life.

One in four people aged five to 17 and almost half of those aged 18 to 24 are affected by overweight and obesity, with reliance on technology playing a huge part.

With new marketing avenues for unhealthy foods and easier delivery through online services, it's as simple as ever to practice poor eating habits.

"Mounting evidence suggests fiscal and regulatory measures are essential for managing population-level obesity," the authors of the Sax Institute paper write.

"Co-ordinated action is needed to support young people to lead healthy lifestyles through personal empowerment and environments that promote healthy decision-making."

Australia has been left behind by the rest of the world when it comes to laws fighting obesity.

The country is relying on a pledge from the sugar-sweetened beverage industry to cut sugar in their drinks by 20 per cent, compared with taxes in place in 50 countries.

Adolescents surveyed said the main threats to their physical health were the "toxic" social media environment and manipulative food marketing strategies, along with venues being inaccessible.

Recommendations from the authors include co-ordinated action to life nutrition and health literacy, along with extra support for youth in rural and marginalised communities.

Monash University's Michelle Gooey says responding effectively to the youth obesity challenge would mean "moving away from a narrative of blame and individual responsibility, which promotes stigma, and focusing on treatment and prevention".

Australian Associated Press