'You've lost weight'

At the gym tonight one of my fellow gym-goers said to me, You’ve lost weight.
I thanked Rona. But I told her that my weight is actually going in the other direction. Her husband, Jim, mentioned the whole thing about muscle weighing more than fat. I have always thought that was a myth. I mean a pound of feathers weighs the same as a pound of bricks, right?
I used Google to learn a little more and found this. Muscle and fat weigh the same. But the difference is: “A five pound pile of fat will take up more space (volume) than a five pound pile of muscle.”
I was so tired after work. I really didn’t want to go to the gym. But I knew I needed to exercise. I got to the gym and Zumba was canceled. The instructor was sick. I don’t really like the Wednesday night spin teacher, plus I didn’t have my clip shoes. So I caught up on celebrity news and worked out on the elliptical. After my workout I found out that the spin class had a sub.