Fast Food FAQ: Myths, Facts and History

White Castle, founded in Wichita, Kansas, in 1921, is widely considered the first fast food hamburger chain.

Several places claim it. Red's Giant Hamburg in Springfield, Missouri, is often credited from 1947, and In-N-Out used a two-way speaker in 1948.

Salt boosts flavour, helps preserve and texture processed ingredients and makes food taste consistent. The FDA Daily Value for sodium is less than 2,300 mg a day.

In the US, yes: restaurant chains with 20 or more locations must post calories on menus and provide other nutrition information on request, since 2018.

It depends on what and how often. Occasional meals fit into a balanced diet; watch portion sizes, sugary drinks and sodium.

So the corners stick out of the round bun, showing off the beef. Dave Thomas liked the idea of not cutting corners.

Subway and McDonald's have long been the top two by number of restaurants worldwide, with the order changing as stores open and close.

Counter-service restaurants with higher-quality ingredients and prices, such as Chipotle, Panera or Shake Shack.

It varies by chain and country. Some use beef flavouring or shared fryers, so check each chain's ingredient list.

Often they are customer-created combinations that staff recognise, like In-N-Out's Animal Style. They create buzz and loyalty.