Article writing about health/nutrition

I'm looking for a writer which is creative, knowledgeable about health and nutrition, and have good English. I need one article each week, will be about 1000 words or we'll do two per week and they'll be about 500 words each. Articles must have no grammar mistakes, be slightly humorous, be interesting above all and fun to read. I'm picking pay-per-time but I don't really care much actual time each will take you but the total price, pay-per-time simply has a much lower fail rate. Will do this project for one two posts and in case it will be successful we'll continue with articles every week. Looking forward to working with you