In order to answer your question, it's best to review how the
body's energy systems work. An article called "Death by Prowler"
by Matt Reynolds has a good overview. It's an educational read,
but I'll summarize a couple high points here: - Aerobic activity
burns more fat in proportion to sugars. - Aerobic metabolism
does not shut off when you push into higher demand energy
systems (i.e. anaerobic activity). Based on the Katch McCardle
algorithm, resting metabolic rate is most affected by the lean
mass you have. I.e. more lean mass, more calories burned at
rest. Now, the bottom line is this: you will burn more calories
per given amount of time when you exercise at an anaerobic
level. The major caveat is that you won't be able to keep up the
anaerobic exercise as long as you can aerobic exercise. Even
though the majority of the calories burned during exercise will
come from blood sugars/glycogen in an anaerobic state, the body
will have to free energy from your fat stores to make up the
energy demands. This is w