Which method of determining resting metabolic rate is more accurate?

Answer 1

Is it more accurate to use your gender, height, weight, and age to determine your resting metabolic rate or your weight and body composition? In other words, does gender, height, total body weight, and age really have a direct impact on your metabolism, or are these formulas based on typical lean mass differences between such factors, and formulas based on how much lean mass and fat mass you have more accurate?

For example, would a male hypothetically have a faster metabolism than a female at the same height, weight, and age, with as much or more lean mass, would someone of either gender have a faster metabolism than someone of the same gender, weight, and age, but who is shorter with as much or more lean mass, and does the metabolism really slow down with age if you were to stay the same height and weight, but continuously gain muscle by working out regularly? Or if you were to gain weight, would the impact really be the same regardless of whether you were getting fat or more muscular?