If you think this is delicious, you must usually eat really bad food!
「いつもどんだけ不味いもん食べてるのって感じ」= You must be used to eating some really bad food! / If you think this is delicious, you must usually eat really bad food!
ボキャブラリー
used to eating = 食べなれている
really bad food = とても不味い食べ物
think = ~だと思っている
delicious = とても美味しい
usually = いつも、普段
must = ~だろう、~にちがいない