Buddhism and the Diet Practices view from other religion
Whether plants have consciouness or to what extent doesn't obviate the fact that persons need sustenance to grow etc. There can be moderation in consumption however, &amp; nonwaste of foodstuffs, lumber etc, which too is efficient from resource utilisation standpoints. Plants do react to light &amp; water &amp; wind etc, yet typically plants are described as nonconscious by current western science, &amp; don't have neural systems, so, sort of depends on how consciousness &amp; volition are being defined.
Consuming animal flesh is perceived as ok by them, so if sharing dinner etc with them such menu items would be reasonably expected. They are being friendly &amp; generous in their way, &amp; it's nice of them to share their time &amp; their resources. If persons select to notconsume animal flesh for whatever reason, good friends might make allowance for that and have some nice things to eat other than animal flesh: bread, potatoes, beans, tomatoes, lettuce, etc. So maybe good to appreciatively consume those items &amp; forego discussions re what the hosts are consuming. They will observe the example of someone notconsuming the animal flesh. And consuming some lobster from a can &amp; which would otherwise be discarded is different from participation of obtaining/ demise of live lobsters. And they may offer thanks for having food &amp; ok health etc, which seems reasonable to observe, and less so thanking for factory farms etc. And to some extent nutritional considerations may be valid. Moderation &amp; nonwaste, &amp; noncontribution(even indirectly) to demise of living things is generally good. To gently show is different from causing sadness or distress to them by comments that they don't understand, and activies which on their part were kindly intentioned. Maybe sidestep such situations is generally good, and each situation may vary.
Nonparticpation in the demise of things, and of such venues, shows by example: and if specifically asked, perhaps could offer a brief explanation, &amp; if presented nicely, might have more good result than more emphatic responses. Good friends would generally be respectful of views differing from their own, so maybe try and use gentle words if commenting on such things, or if replying to a sincere request for information. And perhaps even gentler &amp; briefer if such topic might arise during lunch or at dinner etc.