Duolingo Help Please - “de” vs. “de la”

Why oh WHY does “de” etc need to be in front of these food nouns? I understand the difference between de and de la and du, my issue is with the word itself. Duolingo previously allowed “je ne mange pas de viande” without the “la” which I assume loosely translates to “some”? Okay, so why when we change the subject to “nous” does there NEED to be a “la” why is not just “de” fine? I’m sorry if this is all frustrated gibberish