the paleo diet is a growing diet/lifestyle based on eating real foods. If anything else its very interesting to read about. http://freetheanimal.com/ancestral-life-way is a great blog for anyone interested.
Check out http://wholehealthsource.blogspot.com/ , http://www.marksdailyapple.com/ and http://www.westonaprice.org/ for more viewpoints.
The general consensus though is to avoid processed foods and stick to whole foods. A big one is to eat animal fat instead of industrially produced vegetable and seed oils.
Also, limit carbohydrate intake (ideally eating only fruit and vegetables).
http://www.psychologytoday.com/blog/p-nu/201103/dietary-mani...