Personal Trainer Q and A
Should I work at a lower intensity to burn more fat?
Many people are misled by reading the "fat burning zone" charts on popular cardio equipment. While it is true that your body uses a higher proportion of fat over carbs as a fuel at lower exercise intensities, your total caloric burn will be higher while working at a higher intensity. In addition, the number of calories your bodies uses to recover from exercise will be higher after high intensity work. Therefore, overall you will burn more calories at higher intensities. Please remember, constantly training at high exercise intensities isn't for everyone. Many individuals will be more successful by working out for longer periods of time at lower intensities. An effective exercise program will incorporate the right amount of low and high intensity work for each individual. By evaluating your abilities, your personal trainer should regularly incorporate individualized intervals into your program for an effective and challenging high caloric burn workout.

What the research says: Phelain JF, Reinke E, Harris MA, Melby CL. Postexercise energy expenditure and substrate oxidation in young women resulting from exercise bouts of different intensity. J Am Coll Nutr. 1997 Apr;16(2):140-6.