As several people said, in English, "consume" is a general word. We consume food, drink, air, cigarettes, drugs, breath mints, paper towels, cleaning products, news, entertainment, etc. So this person could be consuming almost anything. In this sentence, translating "consume" as "eat" makes the most sense to me, but I can't say why.
In Spanish, "consume" may have a specific meaning, but if so, it wasn't in Duolingo's list of suggestions. Would a native Spanish speaker please tell us what you know?
I tend to agree with wikitiki here. I don't know what this is really supposed to be saying in Spanish, but the only translation in English that makes sense is something along the lines of "If you're paying, I'm eating". The exact verbatim translation here just doesn't measure up.
well, it isn't really exactly like eat, it's partially the same it can mean smoke/eat/drink etc., this is what dictionary,reference.com has to say about it: con·sume 1. to destroy or expend by use; use up. 2. to eat or drink up; devour. 3.to destroy, as by decomposition or burning. 4. to spend (money, time, etc.) wastefully. 5.to absorb; engross.