[Cynic]

Keep in mind the goal for the workout.

A fuller quote is:

"...if you were looking to build muscle, you might do supersets of exercises for the same muscle groups...Or to create a more time efficient workout, you might do a set of bench presses followed by a set of rows...For exercise efficiency, the worst thing you can do is pair up two exercises that have absolutely no relation to each other...But that kind of inefficiency is perfect for fat loss."

Now, drawing a conclusion from the previous two, the fat loss workouts are not time efficient, thus you're working longer. FLI takes me 1 1/2 hours.

They are muscle maintenance workouts and only for the most green will they build muscle to any degree.

They are metabolically hyping workouts and if done right, keep the metabolism at an elevated stated for up to 48 hours.

One last thought: the human body is an adaptation machine. It's constantly adapting to it's environment. That is how hominids and early humans survived lean times, by adapting. If you make the workout physically efficient:

1. It won't be working as hard and it's the body's attempts to adapt to stress that cause progressive development (fat loss, muscle growth, etc).
2. The body will adapt faster and the workouts won't be as effective for as long and you don't want to have a whole new workout each time you hit the gym. The adaptation must be encouraged, but also made difficult to attain.