The link between muscle mass and energy expenditure

It is quickly becoming known in the health and fitness industry that to lose weight, an individual is required to burn more calories/kJ than they eat, i.e. be in a calorie deficit. The amount of energy (kJ or calories) we burn every day is based on our basal metabolic rate (BMR) to begin with. Our BMR is the rate of energy expenditure per unit of time (i.e. calories in 24hrs) if the individual were to lie in bed all day and not move.  On top of this, we burn more calories with being upright, movement and physical activity. This is our total daily energy expenditure (TDEE). Every person's TDEE is different and is influenced by how active the individual is every day etc. 

So as our BMR is the number of calories that we burn without doing anything, it would be hugely beneficial to increase this number in any way possible (and also increasing TDEE is important but that is another topic altogether). This can be done by increasing muscle mass. Muscle is active tissue and requires energy constantly in order to complete all of its cellular processes. Hence, it can be shown that a higher muscle mass increases BMR, because there is more muscle requiring energy to function every second. This can be beneficial for weight loss as an increase in muscle mass will increase BMR and TDEE as a direct result, creating a calorie deficit. 

Not only does increasing muscle mass have positive effects on BMR and visceral fat levels, resistance training which increases muscle mass also increases caloric expenditure post-exercise (another post to come).nd insulin resistance. However, with a higher muscle mass (in particular in the lower limbs), there was a decreased visceral fat mass. This is a fantastic indicator that increasing muscle mass is very beneficial to an individual's health. 

Not only does increasing muscle mass have positive effects on BMR and visceral fat levels, resistance training which increases muscle mass also increases caloric expenditure post exercise.

References:

Zurlo, F., Larson, K., Bogardus, C., & Ravussin, E. (1990). Skeletal muscle metabolism is a major determinant of resting energy expenditure. Journal Of Clinical Investigation, 86(5), 1423-1427. doi: 10.1172/jci1148

Yagi, S., Kadota, M., Aihara, K., Nishikawa, K., Hara, T., & Ise, T. et al. (2014). Association of lower limb muscle mass and energy expenditure with visceral fat mass in healthy men. Diabetology & Metabolic Syndrome, 6(1), 27. doi: 10.1186/1758-5996-6-27