Total Weight, Fat, and Lean Mass: Difference

We've got our weight, which is measured in pounds or kilograms. Another weight is usually broken down to a total weight fat mass. And there's fat mass that's both in the in the visceral fat, which is under, inside the gut lining. And then there is fat free mass, which is commonly called lean mass. Then there's skeletal muscle mass. These two things are not the same. Fat free mass is everything that is not fat. So, for example, your brain, your bones, your liver, your circulating blood volume, your connective tissue, your spleen, and all these enlarge. Not your brain, necessarily, but most of the organs enlarge as somebody gets heavier. So, for example, somebody weighs 300 pounds, has substantially more circulating blood volume than somebody weighs 150 pounds. Skeletal muscle mass refers to pretty much all the muscle except the muscle of your heart.