I looked at all the reviews, checked the size chart, and according to my size which is 5'8 at 215 pds. ( I'm average with a slight (ha ha )  belly fat )
I ordered a 2X.
It fit a little loose like I wanted it to--I hate real snug fitting clothing.
Anyway it fit great and it felt comfortable.
You don't have to be just slender to wear this, just average.