Matthew 6:16

Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may be seen of men to fast. Verily,, I say unto you, they have received their reward. But thou, when thou fastest, anoint thy head, and wash thy face; that thou be not seen of men to fast, but of thy Father who is in secret: and thy Father, who seeth in secret, shall recompense thee.

Fasting, like prayer and alms-giving, is clearly indicated as a Christian duty, but is delimited by these words to the status of a private, personal, and individual devotion. Widespread neglect of this duty does not countermand it. However, it certainly does not lie within the province of any religious organization to "command" fasting or to prescribe abstinence from certain meats. Such church regulations are identified with the apostasy by Paul who said,

In later times, some shall depart from the faith ... commanding to abstain from meats, which God created to be received with thanksgiving by them that believe and know the truth. For every creature of God is good, and nothing is to be rejected ... (1 Timothy 4:1-5).