I imagine the "fast" in the diet name refers to (the claimed) speed-of-results, but there's certainly an element of calorie restriction (aka "fasting") in there, as well. As Rosie O'Donnell said, "Eat less, move more". I don't know about riding "fast" -- at 280lbs (I was 300lbs), it's all "fast". But don't make "fast" weight loss a goal -- you didn't put it on "fast", and it won't come off "fast", either (at least, not in a healthy and/or sustainable manner). Just my 2-cents (and 75lbs lost, thus far).