There are 7 important nutrients that you can’t (at least not easily) get from plant based sources.

http://authoritynutrition.com/7-nutrients-you-cant-get-from-plants/

This is one of the (many) things I do like about the Paleo Diet – while making sure you get plenty of veggies and tubers, you still eat meats.  I feel that, at least for me, this is the best diet plan around.

BONUS:  Here is a link to a report on how much Vitamin D you need in order to prevent bone disease and a host of other problems.

http://authoritynutrition.com/how-much-vitamin-d-to-take/