Without proper nutrition, an exercise program is useless and can sometimes yield worse results then if not not exercising at all with proper nutrition. Therefore, it important that information be provided yet at a level within your scope of practice. This should be commensurate with your knowledge, skills, and abilities attained from an education and tested within a certification. Depending on the certification and level of education of a health/fitness professional this can extend to providing “general” nutritional advice. The difference between crossing into the field of dietetics is when you get “personalized” and doing dietary intake assessments, counseling, and evaluating and prescribing nutrition. Like LaRue mentioned, the MyPlate and USDA recommended daily intake are good starting points for providing general nutritional information. It is all about education – energy balance, essential nutrients, food density, food in a normal daily diet, whole food vs adulterated, food and supplements of good sources of essential nutrients, principles of good nutrition and food preparation…
This should give you some room to work.
Source: Sass et al. 2007
Fuel the Movement,