The word outdated isn't typically used in the context of food freshness.
The adjective outdated suggests something is no longer widely in use or is unfashionable. Wearing poodle skirts is generally considered outdated. Super Nintendo and Windows 95 are outdated. You wouldn't typically say your food is outdated (unless its presentation or ingredient usage has gone out of style).
"Expiration date" is a term used to indicate when either the shop has to stop selling the item ('sell by' date) or the date by which it must be consumed ('use by' date). If the freshness and overall quality of the product is more of a concern than health issues (for example, crackers go stale but are largely safe to consume after their expiration date), one might use the term 'best before' or 'best used by' date.
But, generally speaking, if food is said to have "expired", that generally means it should not be consumed. It is only historically that items (like milk) were labeled somewhat ambiguously with terms like "expiration date" — which, in the case of milk, was the date it needed to be sold by — but laws varied by product. Product labeling of expiration dates is typically a bit more specific now.
Both are understandable, but there is a difference in meaning based on the speaker's frame of reference.
If the speaker is not going with you, then "If you go, take your lunch" is most natural.
If the speaker is at the destination already, then they sound most natural saying "If you come, bring your lunch"
"If you go, bring your lunch" is an interesting case.
This has both the person moving away from the speaker, and the lunch coming towards the speaker. This seems like a contradiction, but has a few uses!
If the speaker:
- will be at the destination
- will not be travelling with you
- AND is not already there
Then they might say "if you go, bring your lunch".
For example, you and your friends are all meeting at a park and your friend calls you on the phone before leaving.
Another case for this usage is if the speaker is empathizing strongly with you, like perhaps a parent to their child - especially if there is a sense of teaching or admonishing.
Best Answer
I think I understand where this question is coming from - in Hindi, we say "Khana le liya?" to ask if someone has finished having their meal, and that would literally translate to "Did you take your food?"
So going by this, if you want to know if someone has finished having a particular meal, "Did you eat your food?" would be correct English.
However, "Have you had your <meal>?" would be more appropriate than "Did you eat.." (unless you want to make sure that they've eaten everything that was on their plate, as with children).
Here <meal> can be replaced by breakfast, luch, dinner or tea/snacks depending on the hour of day and customs.
If you want to know if they have remembered to carry their tiffin box or some such thing, then "Did you take your food" would be the statement you'd want to use.