I reckon you should stick to the first idea! It's hard to tell either way. 154lbs could look rather fat on a woman of average height, or it could not.
You've gone to a ridiculous extreme there - as the OP keeps saying, this dude is used to athletic "fit" gym types, or as she last put it "fitness instructors".
Involving the type of figure you described in your post there might confuse new posters as to what is actually the issue here.