Burgers

A burger can be a thin patty in a small bun or a tall stack of beef, bacon, cheese and sauce. Fast-food counters make both; the Whopper's grilled patty tastes different from the softer, saucier layers of a Big Mac. A cheeseburger is easy to hold in one hand, while a Bacon King is much harder to finish neatly.

People buy them at drive-thrus, shopping-centre food courts and late-night high-street outlets in all kinds of weather. On a hot, humid day, cool lettuce and tomato may change how refreshing a burger feels, but not its portion. Buns, toppings and extra patties account for much of the difference between orders.