A: Mary is so slim. She looks good even in a plain T-shirt and jeans.

B: She’s a gym bunny and spends most of her leisure time working out.

Note: A gym bunny is someone who spends large amounts of time working out for the sole purpose of “looking ripped.” The difference between a gym bunny and someone who just works out a lot is the latter exercises to be able to do physical stuff like moving heavy objects on a regular basis, whereas the gym bunny does it exclusively for visual reasons and probably couldn’t do anything with those perfectly toned muscles if they had to. A gym bunny often talks with friends about how much time they spend at the gym and acts as if their physical fitness by itself makes them better than others. The word has a little derogative connotation as it is associated with being “vain and superficial,” according to urbandictionary.com.