You have a number of options, many of which are better than "See ya!".
- Say "I have to get some food. Do I absolutely have to be here for this, or will the notes tell me what I need to know? Can you fill me in later?". Any boss who doesn't let you eat when asked is going to be a pretty nasty one.
- Stay through the meeting, and when it's over go out and get some lunch. Obviously this works only if you don't have items in your schedule for right after lunch. If you do have things scheduled right after lunch, it should add extra weight to option 1 being accepted.
- Ask your boss if you can order food you can eat (from the pizza place) and put it on expenses. Make the call yourself and get it delivered. Treat it as an expense to be reimbursed.
A lunch break is legally mandated in the US. While they could reasonably make you wait until after the meeting to take your lunch, they can't make you skip it.