Is food included in the first class trains?

No, it isn’t. 

ONLY in GB and ONLY on SOME IC-trains-and there are reports that some now check for what ticket and only dole out to those who have tickets sold at sky-high price in GB and not those cheapo passholders.

A very few other trains have superdeluxe extra 1st cl and these require an extra costly REServ-and then you maybe get a stale sandwich extra. BUt a few others who have that bar passholders from sitting with the honorable executive class bisnismenny.

AT=Austria has also lounges with cf/T/drinks and some snacks for free-DE has them too, but will not allow passholders in. OeBB also has staff canteens with quite cheap 3-course lunch time meals-for anyone (pay a little more as staff). Always very close by to main stations.