Despite everything you've said about not feeling fine, it seems like you're eating quite well.
ご質問ありがとうございます。
「なんだかんだいいながら[よく食べる](https://eikaiwa.dmm.com/uknow/questions/133179/)じゃない」は英語で「Despite everything you've said about not feeling fine, it seems like you're eating quite well.」と言えます。
ご参考になれば幸いです。
You seem to be eating quite well for someone who doesn't have an appetite.
この場合、次のような言い方ができますよ。
ーYou seem to be eating quite well for someone who doesn't have an appetite.
「食欲ない割にはかなりよく食べてるね」
to eat well「よく食べる」
appetite「食欲」
ご参考まで!
You're eating a lot, despite all your complaining!
Look at you eat, after saying you had no appetite.
「なんだかんだ言いながら」というニュアンスは、despite all your complaining(あれこれ不平を言っているにもかかわらず)という表現を使うと上手く伝わります。
・You're eating a lot, despite all your complaining!
(なんだかんだ言いながら、結構食べてるじゃない!)
・You said you weren't hungry, but you're clearing your plate!
(お腹が空いてないって言ってたのに、完食してるじゃない!)
clear one's plate(皿を空にする)と言うことで、よく食べている様子を強調できます。