Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Current squat: 157.5 x 2
Remember, your heart is the indicator that tells you how many calories you are burning. The faster it's going, the more calories you're burning. If your heart is at a state of rest, you are burning the bare minimum number of calories required to survive.
Strict anaerobic exercises elevate your heart rate much higher than aerobic exercises, -- so you burn more calories at a higher rate of speed -- but the heart rate spike only lasts for a minute or two. That means over the course of an entire routine you don't burn as many calories as you would if your did high rep/low set -- aerobic -- exercises.
However, -- and more importantly -- you need to consider the fact that the more muscle groups you challenge each exercise, the more calories you burn. The high quantity of calories burned is a result of a prolonged heart rate spike.
Stressing several muscle groups at once forces your heart to pump oxygen into more space, so it takes longer for your heart to do its job, so it must pump faster for longer, which is a prolonged spike.
That being the case, power lifts at medium to high reps and medium to high sets -- are going to burn more calories than any other exercises. In other words, don't worry about the amount of weight you're lifting, worry about the number of muscle groups you're stressing each exercise.
If you want to lost weight working out in a gym, do high rep/high set power lifts: cleans, squats, dead lift, bench, clean and jerks... and plyometrics.
Avoid isolation lifts like preacher curls and machine leg extensions. If you're not spiking your heart rate, you're not burning calories and if you're not sustaining the heart rate spike, you're not burning enough of them.
Last edited by Ryan Jon; 03-13-2013 at 12:09 PM.