Dollar for dollar it is the McDonald’s McDouble cheeseburger. A buck plus taxes in the States; 1.39$ here.
So says a commenter on the Freakonomics blog. Freakonomics was written by economics writer Stephen Dubner and professor Steven Levitt and is about the hidden side of everything. I am working from Kyle Smith's column in the New York Post earlier in the week where he also pointed out that "Junk food costs as little as $1.76 per 1,000 calories, whereas fresh veggies and the like cost more than 10 times as much, found a 2007 University of Washington survey for the Journal of the American Dietetic Association. A 2,000-calorie day of meals would, if you stuck strictly to the good-for-you stuff, cost $36.32, said the study’s lead author, Adam Drewnowski."
Slightly higher in Canada.