Our scope of practice is supposed to hold us to recommending the nutritional guidelines provide by the USDA, etc. We are not supposed to be telling clients what to eat specifically. We can make general recommendations and give examples of foods that are high in fiber, nutrient dense, etc. When we tell clients to eat a specific food, we cross the line. Registered Dieticians have the scope of practice to make specific recommendations and to design menus and diet plans. Just stating the reality of nutrition. Many fitness professionals choose to exceed their scope of practice. Ethically and morally, that does not show a professional level of commitment to our industry.
If you want to design diets, go to school to become a registered dietician. Otherwise, we should be limiting our advice to things like target nutritients, meal timing, improving dietary habits, etc.