You without fail always hear ‘fitness pros’ talking about how muscle has a big effect on improving metabolism. The fact of the matter is, it really doesn’t. In fact, each additional pound of muscle you add to your frame increases daily caloric requirements by 6 cals/lb/day. That is IT!
On average, muscle mass makes up about 40% of your bodyweight. However, it only makes up about 20% of your BMR
*Heymsfield SB, et al. Body-size dependence of resting energy expenditure canbe attributed to non-energetic homogeneity of fat-free mass. American Journal of Physiology, Endocrinology and Metabolism. 282:E132-E138; 2002