The best course is the presicion nutrition course. The cours only opens up twice per year and is limited, but the program is second to none. Dr Berardi is the mastermind behind the program and also authored ISSA’s Fitness Nutrition Course which is a great course as well. If you are looking for just a CEC you should look at Nancy Clark, Berdot’ Advanced Nutrition, or Power Eating…cant remember who authored it. I believe all of these can be found on either DSW Fitness or Exercise Etc.
These are the two main places I go for my CEC’s
I’ve just learned about a organization called ISSN.
Here is their link.
Hope this helps.