«خَيْرُ الْعَشَاءِ سَوَافِرُهُ»
The best evening meal is the one that appears in good time.
Sawāfir is connected with being visible or emerging. The proverb favours a supper available earlier, rather than an unnecessarily delayed one.
Its role is rhetorical: the visitor argues against a late and burdensome meal. It should be read as a traditional maxim within the story, not as a precise medical or nutritional prescription.