We have such a litigious society that no matter how experienced a trainer you are, NO ONe who's not a licensed or degreed nutritionist should be dispensing dietary information.
Stick to training and exercise if that's what you're certification or degree is.
Most people seek dietary information from meso or ectomorphs who can eat what they want and still look good matter what.
Client figures, "He/she look good, I'll ask them what to eat."
Not wanting to learn or be trained by an out of shape trainer has some validity to it but would an NFL receiver built like T.O NOT take coaching or advices from someone from like Bill Parcell because he's a fat slob? An NBA player not take rebounding tips from the now rotund Charles Barkley?