Thin privilege is not being judged for using a gym without experience. A thin person who is out of shape can get away with it because they already suit society’s idea of what is attractive.
While I consider myself an athlete (Run, rugby, and do home workouts), I don’t like to use gyms. At my college, I have free access to the gym, but I can only stand to use the treadmill (and only because the outdoor conditions aren’t nice to run in). I run for 30 minutes and then I leave, saving the workout for home.
When I go to the gym, I feel like I don’t fit in; I feel like everyone is silently judging me. I don’t fit the mould of what an athletic person looks like. Unless my shirt says ‘cheetahs (our team) or ‘rugby’, people aren’t going to know. So I just avoid it. It’s a double edged sword. Damned if you workout, damned if you don’t.