In Italian a nice meal is never defined as "Bellissimo"!!
Only "Buonissimo" can be used to comment on food
The adjective Bellissimo describes a physical quality, it is not used to describe taste, flavour or smell:
Un tramonto bellissimo
A beautiful sunset
Una donna bellissima
A beautiful woman
Una melodia bellissima
A beautiful melody
Bene and Benissimo are adverbs, therefore they do not qualify nouns (as in the previous examples) but verbs:
I am well
"Things are very well" translates as:
Le cose vanno benissino
A phrase like that requires the verb ANDARE and not the verb ESSERE.
Also consider the case:
This sentence is to be translated as:
Another similar occurrence would be:
Is everything ok?
VA tutto bene?
It would be wrong to say: È tutto bene? (wrong verb)