Everyone keeps talking about either strength training or cardio for fat loss. What role does muscular endurance training (lighter weights, higher reps) have in fat loss mechanisms?
The reason that the answer to your question is not going to be a straightforward one is that it depends on the number of factors, particularly the type of muscle fibers that you possess, specifically Type I myofibres.
In direct contrast to Type II (fast-twitch), Type I (slow-twitch) fibers contain a much higher volume of mitochondria within the cellular cytoplasm, use more oxygen and produce less force. The main function of these mitochondria is to produce and supply energy for cellular metabolism, sustaining an increased level of endurance. Cells with more mitochondria are more efficient at burning fat (as opposed to glycogen) and will determine the rate and the extent to which you will spend calories.
Therefore, yes: in some individuals, muscular endurance training can certainly play an important fat-burning role, individuals whose muscle fiber percentages are tilted in favor of Type I muscle fibers. In others, with a preponderance of Type II fibers, this type of training will be much less beneficial as far as fat burning goes.