Q. Is it possible to build muscle and burn fat at the same time, or do I need to pick one or the other?
Great question, one I hear all the time. So is it possible to add lean muscle mass while maintaining or even reducing your body fat percentage?
In a word, Yes.
Many in the fitness community see physique change as an either/or proposition: You're either bulking to gain size or cutting to lose body fat, and never the twain shall meet, as they say. Those same people assume that to bulk means to slow your workouts down, while focusing on increasing resistance; and to cut means to train faster and lighter, while doing a lot of steady-state cardio and reducing calories.
Instead of looking at fitness as two stages, bulking and cutting, look at fitness as one stage: maximum exertion regardless of your goal. Instead of challenging yourself in resistance or speed, challenge yourself in resistance and speed! No one has ever experienced poor results from working too hard, so it's time to increase the intensity.
For Exhibit A in what I'm saying, look at most of today's top athletes. These men and women are in fantastic shape. Do you think they are doing extensive steady-state cardio? Do you think they are restricting their diets to reduce their body fat? Absolutely not! These are real athletes who exert maximum effort while training, which leads to an accelerated metabolic rate and enhanced fat-burning metabolism.
No one has ever experienced poor results from working too hard, so it's time to increase the intensity.
By now everyone knows about high-intensity interval training (HIIT), but very few people apply this to weight training. Utilizing this mentality while weight training can and will boost your body's natural fat burning metabolism. At the same time, it can improve your strength and endurance. As long as you fuel your body with sufficient calories to grow, you'll build lean muscle mass while accelerating your metabolic rate.
In other words, to answer your question, you'll build muscle and burn fat.
This back workout offers an example of what I'm describing. Both the resistance and speed will challenge you. Between sets, rest only as long as needed to catch your breath.