Im not super hungry much anymore! Ugh

I eat breakfast (around 11-12) then around (3-4pm) I'll snack n try to eat lunch but just not dinner I'm vegetarian and gluten free is pretty much all I'll eat but my family my mom etc when I come over to my moms everyone eats meat there & I feel bad if I don't eat a Lil at her house she's always cooking etc but how can I eat or get hungry for dinner without being rude to my mom........ I'm mostly at my mom's but me and my SO have our place opinions?!