Unhealthy foods should be taxed the same way tobacco is as part of an effort to battle childhood obesity, Ontario doctors say.

The recommendation is part of an Ontario Medical Association (OMA) campaign launched Tuesday.

The OMA says three-quarters of overweight children will remain so in adulthood, with health effects ranging from diabetes to certain types of cancer and heart disease.

"If we don't start taking immediate action now, our health-care system will soon be overwhelmed by the demands of a completely preventable complication associated with obesity," said OMA President Dr. Doug Weir.

The group suggests that the province introduce policies including:

• Increasing taxes on junk food and decreasing taxes on healthy foods.
• Restricting marketing of fatty and sugary foods to children.
• Placing graphic warning labels on pop and other high-calorie foods with little to no nutritional value.
• Adding retail displays for high-sugar, high-fat foods that prominently advise consumers of the health risks.
• Restricting the availability of sugary, low-nutritional value foods in sports and other recreational facilities frequented by young people.

Just as graphic images are required on cigarette packages, the doctors said, junk food such as french fries should come in packaging illustrating the toll obesity takes on the body. Potential images include a foot with an open wound meant to reflect on a problem that people with diabetes may suffer, or a liver riddled with fatty liver disease.

The OMA is starting its own advertising campaign against low nutritional foods, saying such a move helped bring smoking rates down and could help lead to better eating habits.

The group has not yet spoken with governments or the food industry.

Food and beverage groups called taxing groceries a simplistic approach to a complex issue.

The government of Denmark introduced a tax on saturated fat last year and has abandoned it, Food and Consumer Products of Canada said.

Taxation "does not change behaviour, it hurts middle and lower income families and it costs food and beverage manufacturing jobs," said Jim Goetz, president of the Canadian Beverage Association. "This is a bit of a shame and blame campaign."

Almost one in three Canadian children aged five to 17 — 31.5 per cent — is overweight or obese, compared to 14 to 18 per cent in the early 1980s, Statistics Canada reported last month.

With files from CBC's Aaron Saltzman