It's a hard tack to take, because at that phase you're so focused on one measure -- to be working towards another seems to be a waste of time. However, it isn't. While it may take some time away from calorie-burning, which will directly contribute to your weight-loss, crunches and similar exercise will help build up muscle, which contributes to weight-loss maintenance -- your ability to keep the weight off once you've lost it. Every bit of work you do before you get to maintenance helps. As long as it doesn't take so much away from your short-term efforts that it results in demotivation, you should aim to do as much of that as you can.