Duolingo has been known to apply contractions automatically even when they are not appropriate.
I suppose the automatic contractions are so that contributors can add a translation such as "You have said yes" and an answer of "You've said yes" will be accepted as well without contributors having to add that separately.
But this automatic system doesn't know when this is appropriate and when not.
"If you had told me..." = "If you'd told me....", so this automatic contractor has the rule "you had = you'd".
And it seems that it has applied it to the sentence "What food have you had today?" to produce "What food have you'd today?" even though that's nonsense.
I don't think there's anything we can do about this, unfortunately.
I'd assumed that that was the case once upon a time (and I'm sure that's the case here), but I made a comment upon seeing a similarly apparent error elsewhere and darned if someone didn't pop up from some far corner of the Anglosphere claiming that such usage was perfectly normal where s/he was from. I didn't know if that might be the case here as well.
Before you start worrying that you are seeing things I need to mention that we've had cases where a deleted item reappeared. Usually in a Strengthen skills section or multiple choice. I've sent a report on some we have links for and hope it gets straightened out soon. If it happens again it would be great to have a screenshot or a link. Thanks again for the input.
At the top of this page, you will see the correct translation. It's unbelievable. Nowhere in our incubator does either of the translations you have above appear. This is a ghost sentence that was removed ages ago. Were you on a Strengthen skills exercise? These things have been known to occur there.
"What food had you today?" is incorrect because you need the auxiliary verb "did" since "had" is not used as an auxiliary except when it is part of a complex tense.
The answer shown you is one of a well known Duo computer bug where a verb is incorrectly abbreviated. So instead of "What food have you had today." the computer produced "...you'd...." that is the reason the whole sentence was removed.
Thanks for the screenshot it always helps to pinpoint these errors. It has been reported.
There was no "reply" option because there had been a certain number of replies to a previous comment. You did well to go to another section.
If your reply is common British English we'll add it to the accepted translations.
Thanks for the information about the Strengthen skills exercise. Now I can report it together with the screenshot and let's hope it is corrected soon.