The other important point is - you are the only one who says "Yes" when asked "Is this acceptable to you?" If the free food is not worth $15-20K (which actually seems ridiculous - I've heard numbers for both what average employees value it at and what it actually costs Google, and they're nowhere close to that), then say "I'm sorry, I don't value my food that highly. I'll take the cash or go elsewhere." This, of course, requires that you have somewhere else to go. But remember that Google wants highly-qualified employees just as much as highly-qualified employees want to work at Google.