It depends what area of nutrition you want to go into. If you want to make the effort to get a dietitian license then this is a good route. I see many hospitals, nursing centers and such looking for licensed dietitians. I've also seen some nutrition programs linked with health education licensure programs, which should qualify you to teach health through public health departments and some non-profits. It may also allow you to teach health classes in public schools depending on your states requirements.
You could also go on to graduate school and do research in nutrition and stay in academics.