The proportion of Canadian children who are obese has more than doubled in the last 20 years, according to the Canadian Institute for Health Information.

But doctors say what they're really concerned about isn't the weight itself, but what it's doing to these kids' growing bodies; and the long-term complications they could face as a result of their unhealthy lifestyles.

To keep the dangerous trend in check, some doctors and specialists say their colleagues across the country must start testing obeses children as early as age five.

Adryan Zorec, 14, was recently diagnosed with a serious case of high blood pressure that would be worrisome in an adult male.

Adryan's levels were measured at 140/90. A normal, healthy 13-year-old male's levels would be 90/70.

"I was worried and I was shocked," Adryan told CTV. "I had high blood pressure, and I was like, oh no!"

Adryan admitted it was his penchant for junk food that got him into trouble. He said he ate because he was "stressed," and that eating made him "somewhat feel good."

Doctors warn that Adryan is part of an alarming trend of children who overeat and are far less active than their bodies need them to be to ward off the complications from their ballooning weight.

"We're seeing kids, even before they reach puberty, with blood pressure readings consistent with adult hypertension," Dr. Angelo Simone, chief of paediatrics at the Trillium Health Centre in Mississauga, Ont., told CTV.

Screening urged

The problem is there are no official studies yet concerning overweight children and blood pressure -- just a group of worried doctors like Dr. Guido Filler, who has been keeping a record of his young patients' blood pressure levels over the years.

Filler, head of Nephrology for the Children's Hospital of Eastern Ontario in Ottawa, has charted a whopping 300 per cent rise in kids with high blood pressure since 1985.

The biggest increases, however, have occurred in just the past five years.

"We are seeing a massive increase in referrals for high blood pressure; and I am confident this is a true phenomenon," Filler told CTV. "And it is related to obesity and being overweight."

Filler added that obese children can exhibit very adult symptoms of high blood pressure, including bad headaches, loss of vision and even a stroke in their early life.

Simone and other specialists are urging physicians to start screening children -- as young as five years old -- for all of the complications of obesity, including checking cholesterol levels on top of high blood pressure.

"My worry is that we're missing a huge population of children that have significant obesity, but also all the complications of obesity," said Simone.

Drug drawbacks

For the most serious cases, doctors have been prescribing cholesterol lowering medications for children.

Dustin Rozumniak was 13 when he was diagnosed with a blood pressure level of 210/100 -- a level so high it could kill an adult if left untreated.

Dustin has been on cholesterol lowering medication now for the last three years.

"I could have had a heart attack or stroke and I probably wouldn't be here making this interview," he told CTV.

But these drugs can have side effects, including nausea, constipation and diarrhea, among others. And some of these drugs have never been tested for long-term use in children.

"We often we cannot give new medications and better medications to our children because we don't know how to dose them. There are no pharmaceutical studies," said Filler..

"With this increase we have a growing market and we must know how to dose these medications. And we cannot preclude children from the benefits."

Healthy living

But children like Adryan, whose levels aren't so severe, can usually solve their blood pressure problems with a combination of diet and exercise.

And by living a healthier lifestyle, Adryan has managed so far to lose 20 pounds -- and his blood pressure is back to normal.

"I feel better. I feel I'm getting lighter and I can do more stuff and I am more energetic," he told CTV.

Simone said children have the ability to bounce back to healthier levels as long as they change their lifestyle habits. The arteries of obese children, in general, haven't become stiff like those in aging adults.

"The wonder of the pediatric population is that they are very amenable to change and they are very resilient. So with, at times, six months of intervention, you can bring that blood pressure back down to normal without medication," said Simone.

"So the majority of these kids can really turn things around as Adryan did."

Simone's Trillium hospital is testing out a new program called "Healthy Living," which teaches overweight kids with complications like high blood pressure how to plan their meals, how to exercise and get their famlies involved in a new healthy lifestyle.

It's a program designed not only to get kids healthier, but to keep them healthy throughout the rest of their lives.

Adryan seems to have gotten Simone's message. "It's something that I want to do for a long time," he said.

"You just don't do it for a little while. You keep doing it and it will be amazing what you can do."