This happens when people are among peers and would like everybody to feel equally comfortable and welcome. Weekends, los fines de semana , can be an excuse for the family or friends to get together. Guests usually arrive while the food is being prepared and chat to the host or hostess in the kitchen while the cooking is going on. It is also normal for guests to offer help in the preparations. The meal is usually taken to the table where everybody helps themselves.
Meals often last for hours, the focus being the conversation rather than the food.