There is an abundance of information out there and many different types of publications - books, journals, magazines, websites, and more. It is best to distinguish what information "is for real" on a couple levels. First, if you are going to follow any advice regarding your own activities, you want to do things that are actually going to be a benefit. If you want to makes changes to your diet and/or physical activities in order to improve your health, you want good advice. Second, if you are going to do school work in any way related to nutrition or exercise, you want to make sure the information is reliable and has successfully been evaluated by experts in the field. 

One way to make sure you are using reliable information is to use information from peer reviewed journals. Articles in peer reviewed journals have undergone review and criticism of experts in the field of study. A second way is to use the CRAAP Test to evaluate the information. This is particularly true when using information on websites.

The CRAAP test stands for Currency, Relevance, Authority, Accuracy and Purpose. These 5 criteria are highly important when looking for reliable and reasonable sources.

• Currency asks about the “timeliness” of the information, i.e. how recent the information is or whether it was published during the appropriate time.  Is it critical to have up-to-date information relevant to your topic or issue? Is newer material available? Or Is it better to have older materials?
• Relevancy is a criterion questioning if the information is applicable in the context you would like to use it.  Does the resource cover the issue or topic you are researching, does it help you answer your question, or does it just barely touch upon it?
• Authority. Nowadays, almost anyone can publish information, in particular on the Internet, so it is essential to know the source of information. Who is the author(s)? What credentials do they have? Can you verify their status and/or find other work they have done? Talking about the Internet, you have to keep an eye on the URL. If it says .org, .edu or .gov, these sites are more reliable than the .com-sites since the facts given are usually verified and only members and authors of this site are allowed to publish there.
• Accuracy refers to the reliability, correctness and truthfulness of the information distributed. This criterion focuses on the source of information, the language, and whether or not it contains biases, grammatical errors, or spelling mistakes. 
• Purpose. The final principle when selecting information from other sources concentrates on the question “why was the information published?” For instance was the information published to entertain, to teach, or to persuade the audience? You need to decide.