Are high intensity intervals or longer periods of low intensity cardio better for fat loss?
The most common recommendation for fat loss is low intensity, long duration exercise based on the fact that the body uses more fat as a source of fuel at lower intensities and more carbohydrate as a source of fuel at higher intensities of exercise. While it is true that a higher percentage of energy comes from fat during lower intensity activity, the “total” energy expended is less at lower intensities. As the intensity increases, the amount of energy expended increases; at higher intensities, the amount of energy expended, from fat, is a smaller percentage of a much larger “total.” Also, numerous studies have shown that high intensity intervals result in significantly greater post exercise energy expenditure and fat utilization than lower intensity exercise. Therefore, considering the total energy expended may be more important than the predominant fuel used for fat loss.
