Body Recomposition Calculator

During a recent discussion about exercise and weight loss, I was asked whether cardio or weight training was “better” for losing weight. Once we got past “Pay attention to what you eat”, we discussed that most studies show basal metabolic rate for muscles and ordinary tissue isn’t physiologically significant for weight loss.

Much of the work builds upon a classic paper, Elia, M. (1992). Organ and tissue contribution to metabolic rate. Energy metabolism: tissue determinants and cellular corollaries, 1992, 19-60., which states:

the specific resting metabolic rates (K(i)) of major organs and tissues in young adults with normal weight: 200 for liver, 240 for brain, 440 for heart and kidneys, 13 for skeletal muscle, 4.5 for adipose tissue and 12 for residual mass (all units in kcal/kg per day).

Additionally, Elia’s proposed adult K(i) values are valid in both nonelderly nonobese men and women however age and obesity adjustments may be appropriate for specific applications.

I wrote this little calculator to demonstrate the point. For a ‘big guy’, dropping 5% bodyfat and gaining it all as lean muscle, gives a caloric change of only 42 calories a day.

Try it out for yourself!