Food for Thought
You will hear this from me repeatedly about dissertation proposals and defenses: please don't bring food. First of all, students should NEVER be mandated to "pay" (with food or otherwise - you've already paid enough with money, time, etc.) to do their dissertation defenses or proposals in this kind of way. Second, you have enough to worry about on the day of these kinds of big events that you don't need to add menu planning to your To Do lists. Finally, it just makes me feel oogy inside when students feel compelled to do this.
That said, I know some people feel compelled to do this, anyway. I can't stop you. I can just strongly discourage you. Which I do.
For your reading pleasure...