Fast food is a type of mass-produced food designed for commercial resale and with a strong priority placed on "speed of service" versus other relevant factors involved in culinary science. Fast food was originally created as a commercial strategy to accommodate the larger numbers of busy commuters, travelers and wage workers who often did not have the time to sit down at a public house or diner and wait for their meal. By making speed of service the priority, this ensured that customers with strictly limited time (a commuter stopping to procure dinner to bring home to their family, for example, or an hourly laborer on a short lunch break) were not inconvenienced by waiting for their food to be cooked on-the-spot (as is expected from a traditional "sit down" restaurant). For those with no time to spare, fast food became a multibillion-dollar industry. In 2018, the fast food industry was worth an estimated $570 billion globally.