I get this quite a bit. I'm a bit heavier than I look. Just a few hours ago a regular customer commented that I probably eat about twice a week and I said that I'm trying to lose some weight which brought out a "Why?". I didn't even feel like explaining that I am about 30 lbs over what I'd like to be. I just said that they are seeing me in all black so it doesn't show as much, which is true. However, it doesn't really show that much when I'm buck nekkid either. I'm just built that way.
My chiropractor once mentioned exactly what Professor is saying. He was shocked that I recovered from a compression fracture so quickly. While he was working on my back I said, "Sorry you've got to push through that layer of fat to do your job." and he replied, "Well, it's not bad. Besides, that is one helluva layer of muscle you've got underneath it. I really don't ever want to have you pissed off at me." He was also still under the effects of having had to give me an ass rub the week before in full view of my X who is huge and was built like a brick shit house at the time and there was nothing "stealth" about his muscles. He had them clearly showing.
Pro Tip: Don't try to lift and move something based on seeing this little bitty girl move it before you. Test the weight yourself first. Two guys have hurt themselves because they weren't prepared to lift something that they thought couldn't have been as heavy as they were because they saw me carrying them first and assumed the weight was far less than it actually was.
A foreman tried to be a gentleman and carry my toolbox for me after I had walked up to him and started yapping. It was more than twice the weight he expected. His shoulder was sore the rest of the night.
Another foreman lifted a toolbox he saw me throw into the bed of my pickup. Not only was I strong enough to lift it on any day, I was PISSED that day, so I sent it flying. When he got done begging me not to drag up and promised that everyone would quit f**k with me, he offered to put my tools back on the fuel truck. He dropped my large tool box and sent my impact guns, sockets, over sized wrenches and sledge hammers scattering. I was PISSED again and he was begging again. This time, however, he was begging for me to not kick his ass. I didn't have to. He hurt his back bad enough when he tried to move my toolbox that he was sore for days afterwards. That and having to crawl on the ground gathering up my shit and putting it back in it's proper place while I stood over him tapping my foot and telling him which drawer everything went in(I'm anal about my tools), well, it was punishment enough.