That's a really great question that you've asked! Yay for girlie questions! hah!
So with my PCOS and at my heaviest (335) I did NOT get a period.. zip nada nothing. Not even once. I was not on birth control either so I never got it, naturally or artificially. When I started losing weight I didn't see a difference in my period (aka I didn't start getting it) until I had lost about 60-75lbs. I don't quite remember when. But after talking to my doctor, we discovered that for me, YES losing weight did help in that area. (As well as eating the foods I should be was a factor too). However because of PCOS my period was still irregular (One period lasted 2 months, then 3 weeks, etc) So if you're irregular I'd reccomend Birth Control.. or talk to a Homeopathic Doctor and you can try natural ways to get your period on track (takes longer though). But yes, my OBGYN figures that when I'm down to a normall weight my period will be normal!!
Sorry for the long reply.. I'm a rather detailed person..