When personal trainers say “a pound of muscle weighs more than a pound of fat”… I’ve seen a few trainers (a couple pretty famous ones actually) posting this lately. What? NO. Just no.
What they mean actually, I really hope, is that muscle is more DENSE than fat; therefore, taking up less space than fat. A pound is a pound is a pound people. Very common misconception, and I used to believe that too, but as a trainer, we need to know the difference so we can explain the difference.
How you know you are gaining muscle and NOT fat is by compiling measurements, frequently.
If your measurements go DOWN but your weight is the same or maybe up a little, then BOOM, you have gained muscle (since measurements are down = inches lost = muscle gain, because muscle is more dense).
However, if your measurements are the same or bigger, then you have probably just stayed the same or maybe have even gained fat.
Measurements and Body Fat Composition Readers (such as my Omrom Body Fat Reader) are proving to be much more effective for understanding muscle gain vs. fat gain, compared to using the long-frowned upon scale to read your weight.