Is it true that muscle is heavier than fat, and if so, is that difference in weight significant enough to meaningfully impact body composition metrics like body mass index (BMI) or how clothing fits? Furthermore, if two individuals have the same height and weight, could one person appear leaner and more toned due to a higher percentage of muscle mass, even though their BMI might be the same as someone with a higher percentage of body fat? Could you also explain the implications of this density difference on how people interpret their weight loss or gain, especially when engaging in resistance training?

Answer

Yes, muscle is denser than fat. This means that for the same volume, muscle will weigh more than fat. A pound of muscle and a pound of fat both weigh one pound, but the pound of muscle will take up less space than the pound of fat.