Whether you're using Google, a journal, or a book you found, it's important that you have the skills to critically evaluate the information that you find--your patients are depending on you!
If you think you can trust everything you find on the Web, just take a look at "Whales in the Minnesota River"!
The Utah Academic Library Consortium has put together terrific guide to critically evaluating information. Take a look at it, and try the online Web Site Evaluator excercise to test your ability to critically evaluate information.
Prof. Walkingshaw has put together some great sites for you to draw your attention to the problem of misinformation on the Web:
The American Dietetic Association Position on Food and Nutrition Misinformation
How Quackery Sells
Nutrition Quackery from The Colorado State University Cooperative Extension
and
Interpreting News on Diet from The Harvard School of Public Health