Kentucky does not limit the practice of nutrition, exempting most of holistic practice through an exemption. However, to use the titles “dietitian”, or “licensed dietitian” you could need to be granted a license by the state, and to use the term “certified nutritionist” you would need to be certified.
Kentucky law states that it will not inhibit any person “who owns a health food store or who manufactures, distributes, or sells health foods, dietary supplements, or vitamins nor shall the provisions of this chapter be construed to affect any other person who provides nutritional or dietary advice or sells nutritional or dietary supplements if the person does not use the title dietitian, licensed dietitian, or certified nutritionist.”
Source: Kentucky Revised Statutes Chapter 310. The State has also produced a helpful guide.