Do I recall correctly that you're a Catholic, or am I thinking of someone else? Maybe you can help clarify for me, because I remember having a hard time keeping it straight even after hearing an explanation of what the Catholic practice is (and was), but IIRC I think that prior to Vatican II it was the practice for all Catholics to give up meat but not fish during Lent (or was it that fish were allowed only on Fridays during Lent?), and I think that is still the case nowadays in a lot of other countries outside of North America. So what exactly is the current fasting practice for Catholics? Or if I misremembered and you aren't Catholic, what does your church do?
As for your question, during weekdays of Great Lent we do not consume meat, fish, dairy, alcohol, or olive oil (this last one depends on jurisdiction; some people give up all oil); on weekends we are allowed to have wine and oil (which makes weekends pretty much identical to weekdays for people like me who don't drink alcohol to begin wtih). It's also supposed to be not just "fasting" but "prayer, fasting, and almsgiving (i.e. doing charitable works)," so like I mentioned before, we don't just fast, but we are also supposed to make more efforts to reach out to and serve others, and we have more prayer services, and there's also a sensibility that it's a good idea to try to refrain from things like entertainment that is not edifying and that draws you away from God. But the dietary restrictions are the easiest concrete thing to point to.
Those dietary restrictions are of course only for people who are physically able to keep those rules; people who have health needs, are pregnant, or just become too weak to do their work if they keep the fast strictly, of course do whatever their health needs require them to do. Also, although it is a universal-for-everyone sort of standard to aim for, it can also be very much a case of everyone's fast is his or her own fast, and if there is any sort of circumstance, not limited to medical ones, then you talk to your priest and come to an agreement about what is a reasonable amount to do. My first year going to an Orthodox church (before I was received), I asked the pastor what he would suggest, since keeping all of those restrictions all at once is a bit much to jump into all of a sudden, and he suggested to at least refrain from red meat, and if I felt inclined to do more to refrain from white meat also, which I thought was an extremely gentle and lenient way of easing me into the fasting season.
I have to say, though, that although that might sound like a lot of foods to give up, because of the communal aspect of the fast--the sense of togetherness due to the fact that we are all in it together giving up all the same kinds of foods, the togetherness of going to the additional Lenten services, and especially the potluck or otherwise communal meals which in my community happen 3-4 times per week and are free--I feel like I am being given, by the Church, much more than I am "giving up." So when I was a Protestant sometimes I would give up something for Lent, just on my own (because I didn't go to a church that observed the liturgical calendar), and when that happened it always felt very dry and I would keep thinking to myself, "Lent is very long!" But with what we do, I really feel like I am being sustained by the Church (spiritually and physically!), and although it's a sober season, it's also very joyous and beautiful. So it is really good to be a part of a community that is doing Lent together and to get that sustenance from the Church (spiritual sustenance from the services, physical sustenance from communal meals).
Hope that wasn't too much more of an answer than you wanted!
“Leave your heart, and look into the face of Christ.” -Andrew Murray