Rapid weight loss?
 

It's certainly possible. There are a lot of variables at play. The systems that regulate metabolism and weight are very complex, and sometimes it releases or holds onto fat according to its own priorities. This is what can cause those aggravating plateaus that happen even when your intake is mathematically correct. Keep in mind that "weight" can also include water weight. If your recent "loose" eating included a lot of carbohydrates, that would have caused your body to store more water, which was released when you cut back on your carbohydrate intake.

I wouldn't worry about it, just keep on track and it'll even out in the end.

I had something similar happen -- I'd been plateaued for about two months, and I had been watching what I ate really really carefully and exercising, but not losing anything. The one weekend I broke down and ate McDonald's, pizza, and Boston Market, plus a whole bunch of cookies. On Monday, I was down two pounds!! After watching my foods again during the next week I lost two more!

That's not to say that eating a whole bunch of crap was a good idea (I felt SO guilty afterwards) or that eating crap will make you lose weight, but sometimes I think you just need something crazy to get you off a plateau. :)

Just take it and enjoy it. HA! Some times your body just needs a little kick. The fact that you stopped and then started watching what you were eating again, triggered something. Good luck.