Sorry about the Trumpian block capitals, but for some reason I can't get the italics feature to work, and I've forgotten the BBCode for it.
I'm not sure that "giving up Lent for Lent" can logically be done. I mean, if you give up Lent, you're not really giving it up FOR Lent, because Lent is about sacrifice, and you can't really sacrifice an act of sacrifice, you can only perform a sacrifice or not perform it. Giving up Lent AGAINST Lent would make more logical sense. I suppose you could TELL people "I'm giving up Lent for Lent" as a kind of joke, which seems quite whimsical to me. Jokes don't have to be highly rational, and I like the idea of poking a bit of fun at the idea of sacrifice, especially as an answer to anybody who asks the invasive question "What are you giving up for Lent?"
In case you get any flak from holier-than-thou types, it's possible to explain your position without denying the validity of Christianity in general:
"Many Christians prefer not to observe this pre-Easter tradition because it smacks of religious duty. Christ said of the Pharisees, "They crush people with unbearable religious demands and never lift a finger to ease the burden” (Matthew 23:4). He often criticized the Pharisees for disheartening the Jews with demands that missed the heart of God. Christ did not establish the tradition of Lent as a commandment for followers to observe. Whether or not to participate is a matter between the individual and God."
https://www.christianity.com/wiki/holid ... -lent.html
It's a polite way of telling them to mind their own business.
Me, I can't give up Lent at all because I never adopted it in the first place. Nobody ever asked me to do Lent, and although I've found out what it's supposed to be, I don't see any point, especially as I'm secular. Even if I wasn't, I still wouldn't like the idea of sacrificing if it's not going to do any obvious good. Some say it brings you closer to God, but I don't see how that would happen even if he existed. If it's something like giving up a harmful thing such as junk food, that's fine, but why not just give up junk food regardless of the time of year? That way you get more freedom to control the degree of the change, and you can pick a time when you're feeling ready to give it a try.