"What are you eating?"

Translation: Co jecie?

[AdamTKincaid]

Why not "Co to jesz?"

[immery]

Co jesz? or "Co ty jesz?" is ok. ( Although using ty jesz is a bit awkward in speaking )

[vytah]

Because "tyjesz" means "you put on weight".

[MagicOfLA]

Well it's fine with me, try to report it.

[immery]

It is not fine. I think a Polish person might say it, but it would be either regional, or highly colloquial.
Why would you add "to" to this sentence?

[MagicOfLA]

Colloquial maybe. I just know that it exists and is used. Somebody else decide if it's correct or not.
And why would you add "to"? No idea. We (in Slovakia and/or Czech Republic) just do. And I know they in Poland do it too.

[immery]

You are right, if it is a set phrase, there is no need for reason. If it is a phrase in Slovakia and Czech Republic then it might be a regional thing somewhere near the borders.

Unfortunately I could not get any google or "NKJP" result for this phrase, all came back was either "po co"- why, or misspelled "jest", or "jeż"

I think more common, at least in my area, (not that far from Slovakia), is "Co tam jesz" - literally what do you eat there, but "tam" makes as much sence as "to".

[mihxal]

I would say that "tam" makes more sense. At least for me it seems normal sentence.

[anna387046]

czego nie jesz is what do you not eat so why not czego jesz for what are you eating

[Tom873317]

Why co and not jaki?

[Jellei]

"jaki" generally is more in the direction of "what kind", like "What kind of bread are you eating?" - "Jaki chleb jesz"?

[Tom873317]

I get what you're saying, but you can ask other "Jaki jest" questions, right? Like "Jaki jest twój ulobiony kolor?"

[Jellei]

Yes. So far I think the "Co" vs "Jaki" is absolutely the hardest question for me to answer, I have no idea how to approach that distinction. Of course it's obvious to me, but how to explain it...

[Tine175312]

I thought the difference was similar to English "co/what" (fully open question) vs "jaki/which" (limited number of choices) ...

Obviously what/which can be used almost interchangeably in many situations. But to me they each have a more 'prominent' meaning, as above (may be an idiosyncratic distinction).

Maybe it was naive to think it was that simple

[Jellei]

"który" means "which".

"jaki" means "what", "what kind of". As in "What bread do you like?"

"co" is the simple "what", as in "What are you doing?"

See me quoting br0d4 here: https://forum.duolingo.com/comment/12283728/What-is-your-answer

[Mirko903131]

What about Co Pan je?

[Jellei]

Sure thing, added.

[WellingtonCatnip]

co za jesz?

[_Joka_]

Why not "Czego jesz?"

[Jellei]

"jeść" takes a direct object in Accusative. The Accusative form of "co" is still "co". "czego" is Genitive. So it works in "Czego nie jesz?" = "What do you not eat?".