After 5:2ing for most of 2013, I somehow lapsed into more like 30:1, if that, until recently. I've just logged into Progress Tracker for the first time in ages, and of course it now thinks I've lost 0.1 lb/week on average. In other words, this messes up the statistics, but I didn't want to just make a mew identity and lose the history. But would that have been the best thing to do when re-starting?
Incidentally, despite not fasting much at all for well over a year, I'm still 12 pounds down from starting weight and only went back up to what had been an annoying plateau earlier. The changes in attitude to food which 5:2ing enabled, especially not eating when not hungry, have been long-lasting and remain quite strong (though not perfect!).