Pam, Orthodox Christians are supposed to "fast" (as I described above) according to a schedule set by the Church. Lent, Advent, Most Wednesdays and Fridays, etc. The Church provides a calendar which is marked with the schedule.
http://www.goarch.org/chapel/calendarThat being said, there is a lot of flexibility. Our Faith is person-based, not rule-based, so we have a practice called "Economia" in which the Priest can be consulted in special circumstances. For instance, a new convert or a person returning to the Church after a long absence may be advised to go at it more gently (sometimes having a hamburger when they're used to steak is all they're up to - and sometimes that is okay!). A diabetic would be advised to make adaptations for their medical needs. A person who receives hospitality is allowed to accept what is offered - "fasting" food or not.
And, not all Orthodox Christians *choose* to follow the rules of the Church. Just as Protestants are encouraged to read their Bible every day, but do not all do so, Orthodox are encouraged to fast, but do not all do so.
Judging others in the Church on the matter of fasting is strictly forbidden.
And, besides all that, I choose to be mostly-vegan year round for a variety of reasons - most of which are not religious.