A Big Mac has 550 calories. Add a medium Coke and fries and you're well over 1,000 calories for one meal, more than half the calories recommended for women daily and almost half of what's recommended for men.

But will knowing that a sausage biscuit with egg is 510 calories change what you order? McDonald's began posting calorie counts on its menu boards last week, well in advance of federal requirements for restaurant chains with more than 20 locations.

Some chains, such as Panera Bread, have been posting calorie counts on menu boards for years. New York City and Philadelphia require them, according to the New York Times.

But the Times also said studies have shown that posting calories counts on menus doesn't appear to have a significant impact on what people choose to eat.

Greenfield's McDonald's locations are a 4550 S. 108th St., 5040 S. 76th St. and 4275 S. 27th St.

Will you order small fries instead of large, knowing that you'll save 270 calories? Take our poll and tell us in the comments.