Updated: Sat Jul. 21 2001 9:04:05 AM

St. Catharines, Ont., has been ranked Canada's fattest city with a staggering 57.3 per cent of its residents overweight, according to study by Statistics Canada at the request of The Globe and Mail and CTV.That's above the national average of 48 per cent.

Canadians aren't fat because they lack willpower. It's far more complex than telling people to smarten up, says David Butler-Jones, president of the Canadian Public Health Association. He says the problems are the result of changing lifestyles.

St. Catharines embodies that change: lush farmland transformed into sprawling suburbs and huge factories, a small town that has seen explosive economic growth and soared to a population of 100,000-plus; a downtown that has shrivelled and made way for shopping malls like The Pen Centre.

Canadians are among the biggest eaters in the world, consuming an average of 2,921 calories daily and getting one-third of those calories from fat. (A moderately active woman needs about 1,800 calories a day and a man about 2,500.)

For the full list of Canada's fattest cities, to discover who buys the most chocolate bars, and which fast foods have the highest calorie counts check Saturday's Globe and Mail, or check back here on Saturday.