It is important for personal trainers to work within their scope of practice. Licensed dieticians and nutritionists are in the best position to give nutritional advice.
I tend to suggest that my clients visit www.mypyramid.gov, however, as an ACSM Registered Clinical Exercise Physiologist that is out of my scope of practice.
Ask yourself, would it be better to take the advice of anyone, even a doctor on the question you posed or would be be better to ask a licensed dietitian or nutritionist? It’s better to be safe than sorry especially in a sue happy society.