Looking for people who write for well-known sites (e.g. Huffington Post)

I'm looking for people who write for some of the biggest sites out there (e.g. Huffington Post). I have a health and fitness blog and I'm looking for people who can do some PR using their position and get me some press on these sites.

I can write the post myself, or you can do it yourself if you have a certain style.

Anything health and fitness related is good, but will consider other sites with a lot of authority.

Thanks