What about the standard three meals a day which is entrenched into the present. In ancient times, there was often not even one meal a day depending largely on food availability. Romans ate one meal daily and considered consuming more meals gluttony. In western medieval times breakfast could not be eaten until morning mass was completed. Lunch showed up as “nuncheon”, an old Anglo-Saxon word which meant a quick snack. It was not regularly practiced until the 19th century.
The main meal of the day dinner became later and later as artificial lighting became available.