I don't remember anymore if it was my first game jam, but several years ago I participated in The Escapist's "Indie Speedrun" which was a month-long event structured instead around participants receiving an individual randomized theme and element to include, then being timed from the moment they received it. They were also allowed to participate multiple times. I made 6 games that way.
The reason I'm bringing this up is because I think the experience very quickly drove away any desire to crunch for game jams. This one was the first 48 hour jam I've done since, and I even figured I'd probably stretch it, but instead I just worked whenever, got up and took breaks, slept, etc.. Further, since I'm more used to 4-7 day limits nowadays (like the ones Extra Credits have been hosting), I think I scoped for 4 days without realizing it.
I think for me personally, 48 hour jams just don't motivate me enough to crunch.