Around mealtime, 你吃了吗 can be a familiar light check-in, not an automatic invitation to eat together.
Around mealtime, 你吃了吗 can be a light check-in between people who know each other well. It can feel closer to “How are you?” than to making dinner plans, so a simple 吃了 or 还没，正准备去 answers it naturally.
The question can also be genuinely about whether you have eaten. Familiarity, the moment of the day, and the relationship help make the social reading natural. Even when it is only small talk, though, it does not automatically mean the speaker is offering to treat you to a meal.
Zhou
刚下班？你吃了吗？
Gāng xiàbān? Nǐ chī le ma?
“Just got off work? Have you eaten?”
Lin
还没，正准备去楼下吃面。
Hái méi, zhèng zhǔnbèi qù lóuxià chī miàn.
“Not yet—I am just about to go downstairs for noodles.”
Zhou
那快去吧，晚了人多。
Nà kuài qù ba, wǎn le rén duō.
“Then go on—there will be a crowd if you are late.”
Zhou meets a familiar neighbor at dinnertime and asks about her meal. Lin simply gives her meal status, and Zhou sends her on her way rather than making plans, so the question works as a light check-in rather than an invitation.
Familiar neighbors in the evening