I first bought the olive green pants in size M (I'm about 5'7", 145 lbs) and loved it so much that I bought the black pair, also in size M. I was looking for a pair of pants to wear to work that still had the comfort of pajamas. I waffled between purchasing M or L and opted for M because of the loose fit below. The waist is tall/wide and it's definitely snug but I still found it comfortable mainly because it landed high on the waist--and that may be because of my body shape (I still have a little belly from pregnancy 3 years ago). I think the fit is really flattering and still appropriate for business casual. In case you had no idea what "tencel" is like I did, it feels like a soft linen.
