I would definitely check with the hosts to (1) see if there’s something they’d like you to bring. Maybe they’ll be happy to have you bring drinks, for example and (2) confirm that whatever you’re thinking of bringing isn’t duplicative (you assemble a fruit salad in your hotel room and then find out, as someone else suggested, two others bring the same). You mention healthy eaters…I would find a low sugar banana or zucchini bread (or similar) recipe and bring a relatively healthy baked good item. They can be made in advance and travel easily.