Dietitian

In my experience, it can be helpful to ask a few questions when talking to a dietician to see if you want to use them .

First, find out their opinion about some common diets out there. What do they think of, say, gluten free diets, low fat diets, low carb diets...a few things like that. Because dietitians are people too, and you'll find that some will have biases. Like those that think a gluten free diet is terrible for everyone, or those who think it's necessary for everyone, for example. So you want to see if you can find one who may give you some good advice, with as little bias as you can get.

Second, find out if they specialize in anything - like, are they very familiar with allergen free diets, diets to lower cholesterol or for weight lifting, etc... That'll be helpful for what you are looking for.

And last, I'd ask exactly what they will give you.

I had to have some medical restrictions on my diet, and have seen a few dietitians. One had a basic: here's what you have to avoid, here's some things that you can eat, here's a few sample menus, have a nice life.

My best one gave me the basics, information on how some of my nutrients affected me and what I needed to be on the lookout for due to my specific diet, plus some good places to get supplements I might need on my particular diet, plus the stores in the area that carried brands I could use AND what those brands were. When we realized one of my allergies made some foods very hard to find, she actually called around to stores and found places i could shop better. She was amazing, but does not seem typical.

Make sure they are a registered dietitian and not a nutritionist