That sounded strange for me, since every time I've visited a hospital, it was a nutritionist that prescribed the diet for every patient. So I looked at the Wiki

That sounded strange for me, since every time I've visited a hospital, it was a nutritionist that prescribed the diet for every patient. So I looked at the Wikipedia link from another comment; it seems that the terminology varies depending on the country. Here in Brazil, "nutricionista" (which translates as nutritionist) is the protected professional designation, and only they can prescribe diets for hospital patients.