Trust there sizing
Bought a 2 XL set of these before christmas. I wanted to make sure that they would stay up and don't have to pull them up everytime I sit down. They fit very comfortable and I don't need to tie the draw string to keep them up.
Feeling comfortable with the performace I ordered a second set, but XL. Overall a better fit for performance (Knees fit tighter and brace better) and still stay in place without sinching the draw string very tight. There is plenty of height in the waist area to ensure a comfortable, all day fit.
These are very warm; they fit and insulate better than most of my long underear. They also wick sweat away better as well so I can go in and out of the lodge multiple times through the day and still be comfortable. I wear them while Ski Patrolling so need lots of bending as well as in and out of the patrol huts.