The weight difference between muscle and fat is a common misconception. How much more does muscle weigh than fat? In reality, a pound of muscle and a pound of fat both weigh the same – one pound. However, the key distinction lies in their density and composition. Muscle is denser than fat, meaning it takes up less space in the body. This is why someone with more muscle mass may appear leaner, even if they weigh the same as someone with more body fat.