Ask yourself: "If my workspace is on the main drag, where is the lowest traffic area for my team?"
You may have common areas or unused meeting rooms to hide in during your lunch break. Or don't forget that if you're in a big building, you'll probably be anonymous to other teams, so you could sit in a different breakroom, for example, and not be disturbed by work questions or other conversations.
Go outside, if you have comfortable options there. Sit in your car if you really want solitude.
You could also invite people to join you for a 30-minute-actually-good-for-you-really-a-break lunch. It might surprise you what happens when people see that it's really not that hard to be a little happier and a little healthier during the day.