The period between c. 500 and 1300 saw a major change in diet that affected most of Europe. More intense agriculture on ever-increasing acreage resulted in a shift from animal products, like meat and dairy, to various grains and vegetables as the staple of the majority population. Before the 14th century bread was not as common among the lower classes, especially in the north where wheat was more difficult to grow. A bread-based diet became gradually more common during the 15th century and replaced warm intermediate meals that were porridge- or gruel-based. Leavened bread was more common in wheat-growing regions in the south, while unleavened flatbread of barley, rye or oats remained more common in northern and highland regions, and unleavened flatbread was also common as provisions for troops.