"des pommes" = "some apples" or "apples". In English, we see both 'apples', and 'some apples' as both representing an indefinite amount of apples, and we refer to group nouns plurally. "Des" in French is a contraction: de+les=des.
Literal translation--> The boys eat of the apples. but because that is not a common way of expressing a part of the larger whole, we translate this sentence as --> The boys eat some apples, OR The boys eat apples (for aforementioned reasons). Now, the real question is this: does this translation mean that, in general, the boys eat apples and therefore apples are a part of their diet? Or, that the boys are eating "of the" apples, from the fruit bowl on the table?