I work in a grassroot store, We (DH and I) didn't open it, but I'm pretty sure that I could answer general questions.
Also my degree is in restaurant management so I have done and helped in business plans for a bunch of different restaurants (both real and imaginary
) I don't know if you were talking prepackaged natural foods or cafe style natural foods. Either way your big things to consider would be location, licenses and distributors. If you can solidify those three things you'll be golden!
I would go for it, if you have never worked or been a part of a small business you have no idea the rewards mentally spiritually and (if your lucky!) monetarily that you will receive!!