I have issues with leggings. I wear them as pants. Yes, loud and proud. My problem is that, as I have to buy the longest pair available, they are much too big around the waist.
It only recently occurred to me that taking the seams in actually only takes two quick lines of sewing with a serger. Duh. So dumb.
Two seconds later my leggings not only fit a bit better BUT THEY ALSO STAY UP. It's wonderful. It's even more wonderful than the first moment that I realised that leggings make comfy pants.
(This would also totally work with a zigzag stitch, if you don't have a serger.)