Both the Eastern and the Western churches ordained that feast should alternate with fast. In most of Europe, Fridays were fast days, and fasting was observed on various other days and periods, including Lent and Advent. Meat, and animal products such as milk, cheese, butter and eggs, were not allowed, and at times also fish. The fast was intended to mortify the body and invigorate the soul, and also to remind the faster of Christ's sacrifice for humanity. The intention was not to portray certain foods as unclean, but rather to teach a spiritual lesson in self-restraint through abstention. During particularly severe fast days, the number of daily meals was also reduced to one. Even if most people respected these restrictions and usually made penance when they violated them, there were also numerous ways of circumventing them, a conflict of ideals and practice summarized by writer Bridget Ann Henisch: