I have flat feet and bunions and alot of trouble with me feet, ankles, knees, and hips. So ive started to use the eliptical machine instead of running like i normally do to lesson the shock on the joints from pounding your feet while running. I have to say that i really like the eliptical machine and feel it gives a real good workout. Ive been doing 60 minutes 3 times a week. One question that I have is that during this 60 minutes i burn 1000 calories according to the machine.. while trying to keep my heart rate between 170 and 180. Is this too much to be burning? Wont this cause muscle catabolism? Ive read Warlobos post about pushing for the extra time and going for the full 60, but im afraid that burning 1000 calories on an empty stomach in the morning cant be good.. before i loose all my muscle and turn into a small guy.. someone please let me know if this is ok..