It is mostly general knowledge that ‘muscle burns more than fat’, but there is controversy as to how many calories are actually used by these two types of body tissues on a daily basis. According to ACE research, one pound of muscle uses 4.5-7.0 Calories per day, whereas one pound of fat uses about 2 Calories per day. This equates to a 150 pound person who is 15% body fat (or 127.5 pounds of lean mass, and 22.5 pounds of fat mass) using 573.5-892.5 to fuel the lean mass daily and 45 Calories to fuel the fat mass. Keep in mind that these are estimations, especially with the muscle mass. “Lean Mass” includes organs, bones, skin, and other tissues not categorized as ‘Fat Mass’.
Also, remember that these are not the only contributing factors to our daily energy needs. Emphasized in the ACE Metabolic Training Workshop https://www.acefitness.org/continuing... , it is important to consider a variety of factors that contribute to our Resting Metabolic Rate, Thermic Effect of Food, and the Thermic Effect of Physical Activity. These include gender, weight, muscle mass, physical activity, non-exercise physical activity, and excess post-exercise oxygen consumption.
In short, muscle mass does utilize more Calories per day than fat mass. So an increase to your lean mass will cause a slight increase in your metabolic rate!