The big problem with fats is how the body utilizes them. Some people turn over fats very quicly and do not store large amounts (just lucky geneticlly speaking), others cannot readily metabolize fats and tend to increase stored and blood "fat" levels. Since many types of fats are potent stimulators of cells this can lead to coronary-artery disease, cancer etc. Remember though that these are chronic problems, eating hihg amounts of fat for shorter periods or occasionally I expect should not be a problem.

I believe the word is Ketosis (related to Ketone bodies in the Kidney/Ketone Metabolism)