An American expert on obesity told a forum Sunday that today's obese children face a future of heart disease, potentially as early as the end of their teen years.

Dr. David Katz of Yale University's school of medicine urged parents to address the exploding problem of childhood obesity.

Katz was speaking to the Canadian Cardiovascular Congress in Toronto on Sunday.

He said the current generation of children is the first in modern memory to look toward a shorter life expectancy than their parents.

He said obesity can trigger Type 2 diabetes, and both conditions are risk factors for cardiovascular disease.

He said modern humans are like polar bears in the desert, incapable of adapting to a changing environment.

Katz said human beings evolved when food was scarce and getting enough to live on required a lot of physical effort.

Katz said he sees a vending machine filled with sugary and fatty food in a school every bit as unacceptable as a vending machine filled with packets of cigarettes.