True. I have also heard people (usually someone’s mom, I think :) say something like, “You need to get some food into you before you start your busy day…”

It's an idiom for getting someone something to eat. Oddly, the idiom is actually a literal description of what will happen: food will go inside the person. But that's not how we normally talk about eating. The sentence means something like, "I thought I should get him something filling to eat ('decent meal') because he is so thin and weak that he looks like he might die soon."