The problem with Scotland's obesity may be higher than expected, as the researchers said, weight calculations may be inaccurate.
Experts from the University of Strathclyde said many healthy young people are "rich in fat" content.
They also warn of the current body mass index (BMI) – risks that underestimate the extent of the problem to half.
Scientists estimate that more than 100,000 young skotts are now obese.
They said using an alternative method of measuring obesity would give "a much more accurate picture of the extent of the problem".
However, they said that the method would be "more expensive" and took more time.
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Prof. John Reilly Strathclyde of the Psychological and Health Sciences College said it could be "worth considering and investing."
He added: "BMI is a simple and cost-effective way to measure obesity in children and has been widely used in national research and public health data, but it is a very good resource.
"A large number of children and adolescents who are obviously healthy for their BMI age have excessive fat content.
"Childhood obesity is at least twice as common as reported in national surveys and in official publications – in fact more than 100,000 Scottish children and young people are getting into obesity at this time.
"The deuterium dilution measure would be more expensive and last longer than BMI – from three to four hours in the 15 to 20 minute BMI – but it would give us a much more accurate picture of the extent of the problem.
"It has to be properly investigated and can be valuable and investing."
Prof. Reilly recently conducted a study on obesity in Africa, involving 1,500 elementary school students in eight different countries.
This found a significant difference between the BMI (9%) of muscle in the defined levels of children and obesity children.
Another method – called deuterium dilution – saw 29 per cent classified as obese.
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Prof Reilly spoke of a report by the Active Global Healthy Child (AHKGA) report assessing the development of childhood physical activity in 49 countries.
The Strathclyde University Specialist was Scotland's AHKGA research, which gave Scotland a D + rating – to invest in the lowest half of the country.
Prof. Reilly continued: "An African study showed the extent to which BMI underestimates the actual prevalence of obesity.
"Together with the Active Healthy Kids report, it suggests that your child's obesity is no longer room for content anywhere in the world, urgent measures are needed to prevent and manage the problem."
How does Scotland compare?
Slovenia had the best ranking of all countries in the category B, while England was given a C size.
However, Scotland's ranking was better than the US that got D, while China was awarded D.
Although Scotland made B for organized sport and physical activity, it got F's high-level seating behavior among young people.
The AHKGA report found modern lifestyles, including the front screen, and automated tasks that had affected the global obesity problem.
Dr. Mark Tremblay, AHKGA Chair and Senior Researcher at the CHEO Institute of Ottawa, said: "We all have a common responsibility to address these cultural and social norms, especially the time of the screen, because active children are at risk of harmful physical, psychological, social and cognitive health problems .
"This generation will face different challenges such as the effects of climate change, the increasing globalization and the consequences of rapid technological change.
"They must be physically active in order to grow into a healthy, resilient adult who can survive and succeed in a changing world."