n. One who diets; one who prescribes, or who partakes of, food, according to hygienic rules.
adv. In a dietetical manner. [ 1913 Webster ]
n. That part of the medical or hygienic art which relates to diet or food; rules for diet. [ 1913 Webster ]
To suppose that the whole of dietetics lies in determining whether or not bread is more nutritive than potatoes. H. Spencer. [ 1913 Webster ]
n. A physician who applies the rules of dietetics to the cure of diseases. Dunglison. [ 1913 Webster ]