Being plant-based our leggings might feel lighter and thinner than your typical thick and stuffy polyester legging. Some people say they're like not wearing any pants at all! Which is great when you're sweating and moving, no one has time for pants that feel like... too much pants! Also, they do contain 5% spandex, which is a petroleum-based ingredient. Without it, your leggings wouldn't stretch and no one- you or the planet- would benefit from a product nobody wants because we refused to add a stretchy element to it. Until we can all exercise in loose woven flood pants and tunics (unlikely), or until someone invents a plant-based stretch fiber (yay science!), this is the best we've got. So much better than 100% plastic though, don't you think?