Adjective : a jar of dietetic jelly.    From Dictionary.com. 

These ultra-temperance dietetical philosophers never flourished greatly.    From Wordnik.com.  [The Atlantic Monthly, Volume 17, No. 101, March, 1866] Reference

Picnics were conversationally considered in all their more important phases — historical, dietetical, and social.    From Wordnik.com.  [Our Mr. Wrenn] Reference

Picnics were conversationally considered in all their more important phases -- historical, dietetical, and social.    From Wordnik.com.  [Our Mr. Wrenn, the Romantic Adventures of a Gentle Man] Reference

True, they had no dietetical elegancies – only fried pork, bread, butter, tea, and syrup, but my appetite was keen enough to be generously uncritical.    From Wordnik.com.  [Janey Canuck in the West] Reference