Lewis & Short

dĭaetētĭcus, a, um, adj., = διαιτητικός, belonging to diet: libri, curatio, Cael. Aur. Tard. 2, 12, 145.
Subst., diaetetici, ōrum, m., physicians who cure by diet (opp. chirurgi), Scrib. Comp. 200 (cf. Cic. Att. 4, 3, 3).