fast food vs nutrition

fast food and nutrition both are nouns.

Word	Noun	Adjective	Verb	Adverb
fast food	Yes	No	No	No
nutrition	Yes	No	No	No

As nouns, nutrition is a hypernym of fast food; that is, nutrition is a word with a broader meaning than fast food:

fast food: inexpensive food (hamburgers or chicken or milkshakes) prepared and served quickly
nutrition: a source of materials to nourish the body

Other hypernyms of fast food include aliment, alimentation, nourishment, nutriment, sustenance, victuals.

fast food (noun)	nutrition (noun)
inexpensive food (hamburgers or chicken or milkshakes) prepared and served quickly	the scientific study of food and drink (especially in humans)
	a source of materials to nourish the body
	(physiology) the organic process of nourishing or being nourished; the processes by which an organism assimilates food and uses it for growth and maintenance