When it comes to torching body fat and staying lean, what really counts is maximizing the number of calories burned after the workout (at rest), not during it — the concept of excess post-exercise oxygen consumption (EPOC), or “afterburn” for the layperson.
The greater the EPOC, the more total calories burned and the more potential fat loss. That said, it appears heavy weights provide a great afterburn.
One study showed that EPOC was higher in subjects who did low-rep sets of 80 to 90 percent of their one-rep max than it was in subjects who did sets of 15 reps at 50 percent of 1RM.
The take-home here: Incorporate relatively heavy sets in the five- to six-rep ballpark on a regular basis in addition to the hypertrophy sweet spot of eight to 15 reps. Both ranges are great for promoting muscle gains and keeping the fat off your physique.