Crossfit for fat loss/muscle definition?

wolveslovemee

Hey everyone-

Today I tried a Crossfit workout for free at a local place with crossfit certified coaches (first time). I have a question concerning the style and general approach to this method as means for fat loss, as Ive heard two contradicting things:

1) Ive heard and been told many times that for optimal fat loss, that a heartrate of around 60-70% is ideal for cardio and should be kept at a steady state for more than 30 mins or at least 30 mins

2) This goes pretty much against what I did today in Crossfit. My heart rate and Im sure everyone elses was SKY high...so how are people losing fat and getting these insanely nice bodies?

Ive been using the Paleo method of eating for about 5-6 weeks now, although of course i have much tweaking to do, so Im not too concerned as far as my eating goes, but Im more curious why Im getting such a conflict of information?

Without starting an argument, would someone who knows some facts be able to point me in the right direction as far as this whole heart rate thing goes?
And if anyone has done Crossfit or IS doing it still, what have you results been like (whether it was for weight loss or general fitness)?