Pet Nutritionist – Experiences?

Honestly, I've never heard of a pet nutritionist. I wasn't aware that people like this existed. I know that vet technicians can offer sound advice for your pet's diet and nutrition. That is basically what my friend does during check ups and such. She works for a Vet Clinic and examines everything prior to the Veterinarian coming in. She has given me advice after seeing my dog and it worked perfectly. She has even given me pamphlet information about nutrition and care for my pets. I'm wondering if his is what you're looking for or are pet nutritionists a real thing? I don't know why, but it seems so crazy to me.