This is the explanation that Yogi Bhajan gave as an answer to a question about the wearing of white natural fiber clothing taken from The Beads of Truth from Spring 1981:

"We wear white because it's a simple scientific fact that every piece of matter or material has a foot and a half aura. Every animal has a three and a half foot aura. Every human has a nine foot aura. And if we wear the cotton and we wear the white, this color therapy gives us one extra foot of aura. So, I trust my students will behave right, but in case they behave like animals, they will still have a margin, an edge. And that is what it's all about. You have to wear a natural fiber and you have to wear white. It's a pure color therapy and it's called auric color therapy"

If you haven't tried wearing white, you should try it.  It makes you feel good.