Fast food is food that is cooked in bulk and kept warm or reheated to order. Many fast food restaurants are part of restaurant chains or franchise operations, and standardized foodstuffs are shipped to each restaurant from central locations. Fast food became popular due to people being busy working during the day and night. It is also easy to get fast food at any time. Fast food consumption has increased since the 1800s and provides convenience but may lead to negative health effects like increased weight and unhealthy hearts.