Q. The equipment at the gym displays the total number of calories burned per workout. Is there any way to know what percentage o

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    This can be precisely determined through gas exchange testing. However, as a rule of thumb, for lower to moderate intensity workouts, up to 50% of the calories may be fat calories depending on the individual's muscles ability to burn fat. Training in the lower intensity zones improves the muscle capacity to burn fat during exercise.

    -- Lesley Mettler, CT, AFAA, USATF