Muscle is metabolically active tissue and fat tissue is not. So, fat tissue contributes nothing to help you burn calories. If you want to burn more calories and fat, even at rest, build muscle mass on your body.
Building muscle mass has benefits beyond making you look physically better and strengthening your bones. Do strength training throughout your life to maintain critical muscle mass and avoid sarcopenia (diminishing muscle mass).
"Muscle is our largest metabolically active organ, and that's the backdrop that people usually forget," said Kent Adams, director of the exercise physiology lab at Cal State Monterey Bay. Strengthening the muscles "has a ripple effect throughout the body on things like metabolic syndrome and obesity."
Historically, strength training was limited to athletes, but in the last 20 years, its popularity has spread to the general public, said Jeffrey Potteiger, an exercise physiologist at Grand Valley State University in Grand Rapids, Mich., and a fellow of the American College of Sports Medicine. "One can argue that if you don't do some resistance training through your lifespan, you're missing out on some benefits, especially as you get older or battle weight gain," he said.
And, as I often say, don’t become a “cardio queen” and neglect strength training.
During cardio exercise, the heart loads up with blood and pumps it out to the rest of the body: As a result, Potteiger said, "the heart gets better and more efficient at pumping."
But during resistance training, muscles generate more force than they do during endurance exercises, and the heart is no exception, said Potteiger. During a strength workout, the heart's muscle tissue contracts forcefully to push the blood out. Like all muscles, stress causes small tears in the muscle fibers. When the body repairs those tears, muscles grow. The result is a stronger heart, not just one that's more efficient at pumping.
A 2010 study in the Clinical Journal of the American Society of Nephrology suggested that people on dialysis can benefit from building muscle.