See that's just it.
I hate to make it a comparison between health professionals and doctors... but you can't expect to go out and become a doctor or have the same level of expertise without reading the messy stuff.
The same can be said about being educated to the extent of a health professional.
I've built my base by reading text book after text book.
There are certainly easier ones than others, but the fact remains that the information isn't easily digestible for most.
And to be honest, I'm not sure there are entry level books worth reading. I haven't come across any, personally. I used to be into bodybuilding so I'd read dietary and workout books written by bodybuilders. From there I learned the basics like the importance of protein or the difference between a 20 reps sets and 5 rep sets, etc, etc.
But I learned a lot of bullshit too. At least I learned that is was bullshit once I got my hands dirty.
Guess what I'm trying to say is not until you get your hands dirty can you decipher BS from quality.
Does that make sense?
I bought my first college level text on exercise physiology when I was halfway through college. If I didn't understand something, I researched it more, outside of that book, and I didn't move on until I felt comfortable.
But it's my passion so it was worthwhile.
To be honest, I think your average person would learn more by subscribing to blogs of those in the industry who are worth listening to and reading their articles on the web.
Yea, there is more bullshit on the web than on the bookshelves... but that's simply b/c the barrier to entry is much smaller.
A good intro book, depending on what you know so far, is Tom Venuto's ebook titled, "Burn the Fat, Feed the Muscle."
Some of it is outdated and he is a bodybuilder but he knows his stuff and packaged a ton of info into one book. Not enough to be an expert but enough to get a broad exposure.