Dietitian

[Britney]

Nutrition expert that requires a degree and is a protected title. They dont want to be told all about how carbs are bad for you or be lectured on something you read about in a magazine and this suddenly makes you an expert on food. No it doesnt! You bell end!
With love, all British dietitians

[Rihanna]

a person who scientifically studies and gives advice about food and eating

[Kit]

An expert on diet and nutrition.