It's been three years since Christophe Legault, now 12, was diagnosed with obesity and started treatment.

He had been having trouble at school — his grades were dropping, he was being bullied and he was struggling to participate in sports such as basketball, his favourite.

The program he's been following at Maison de Santé Prévention, a semi-private, subsidized clinic in Montreal, involves intensive lifestyle and nutrition counselling, including finding out what kinds of food and exercise work for him and his family, who pay for the treatment.

With help from doctors, nurses, nutritionists and other experts, the family made changes around the kinds of foods they eat, and Christophe started walking to school instead of taking the bus. 

"It makes me proud that I made a lot of progress," Legault said. "If I didn't have that treatment, it would have been really hard."

The kind of early, intensive intervention Christophe is part of, is in line with the American Academy of Pediatrics' new clinical guidelines to treat obesity, announced in January. The guidelines shift doctors' approach from so-called "watchful waiting" — to see if a child outgrows obesity — to more aggressive treatments.

The recommendations include intensive, one-on-one health and lifestyle treatment — at least 26 hours over three months, for children as young as two who have a body mass index in the 85th percentile or higher.

But the AAP also recommends physicians offer weight-loss drugs for kids 12 and up with obesity, and referrals for bariatric surgery for teens 13 and up with severe obesity, defined as having a body mass index of 35 or higher.

"Many of these children, especially teenagers, are going into adulthood with obesity and by the time they're in adulthood, they already have many of the comorbidities," said Dr. Madeline Joseph, medical director for the UFHealth Pediatric Weight Management Center in Jacksonville, Fla.,and one of the authors of the U.S. guidelines.

There are 14 million children in the U.S. who have obesity, affecting one in five children across the country, according to the U.S. Centers for Disease Control and Prevention. Joseph said with more than 14 million children with obesity, there evidence has shown the old approach just didn't work.

"We cannot watch these kids really struggle and their health is in jeopardy without offering them some solutions," she said.

In Canada, where about one in 10 children has obesity, treatment guidelines are also in the process of being updated. A team of more than 50 experts across the country is reviewing the latest evidence and consulting families with children who have obesity to determine the best approach.

"Eating less and moving more is a very simplistic view of a complex problem," said Dr. Geoff Ball, a professor at the University of Alberta and a chair in obesity research who is working on the guidelines with the advocacy group Obesity Canada.

"Over time as researchers and health professionals, we've taken a much broader, more comprehensive view of obesity."

Dr. Melanie Henderson, a pediatric endocrinologist and researcher at Sainte-Justine Hospital in Montreal, said obesity is a chronic disease affected by environment, socio-economic factors, genetics, lifestyle and more.

Henderson, who is also working on the Canadian guidelines, said children with obesity are at risk of high blood pressure, cholesterol problems, and diabetes. They also have higher rates of anxiety and depression. Left untreated, children can carry those health problems into adulthood.

"The first line really remains healthy lifestyle choices and working with the families to try and overcome some of the barriers," she said.

Still, Henderson said that treatment doesn't work for all children, and not everyone has access to programs focused on that approach.

"There is a subset of children despite making all their efforts living with very severe obesity and very severe complications," she said. 

For them, Henderson said, medication and bariatric surgery need to be openly discussed as treatment options.

Stigma can also play a role in how children with obesity are treated within the health-care system and beyond, said Dr. Yoni Freedhoff, medical director of the Bariatric Medical Institute in Ottawa.

Focusing solely on lifestyle changes, he said, "adds to the stereotype that it's just a matter of control."

"There's genes and hormones that we can't control and these medications can help level the playing field," he said.

Dr. David Ma, professor of health and nutritional sciences at the University of Guelph, worries that following the U.S.'s lead and including recommendations for drugs and surgery in Canada's guidelines could undermine efforts aimed at prevention.

"Certainly there is some evidence to demonstrate efficacy in individuals, in children, who are the most extreme cases in terms of being overweight," he said.

"The concern is that these are simply Band-Aid solutions and that we really need to get to the root cause of why these children are overweight and obese."

In the U.S. a further set of guidelines is expected that will look specifically at prevention.

Ball said Canada's guidelines, expected later this year, will focus on treatment, for now. He said prevention guidelines could follow but will take the work of many stakeholders – in schools, communities and health-care settings.