Hi M K,
I usually recommend the Academy of Nutrition and Dietetics http://www.eatright.org/public/.
Attending a talk by Roberta H. Anding at an IDEA conference, she suggested this for peer reviewed articles.
Else I draw information from the Center of Science in the Public Interest but their web site is not quite as accessible.
I am anxious to see what my fellow trainers have to say. With nutrition sites, it’s a jungle out there, and it is difficult to find information that has not been obtained courtesy of the company that stands to profit from it.