That’s not possible for a lot of people unless they’re fine with starving.
This is why a network of support and organization during a protest is vital. Because you’re going to have a lot of people in this position, so having some sort of place for donations and distribution of food/funds and a team to coordinate so the protests can continue uninterrupted is important. How to organize such a support network is a problem for people other than me who aren’t introverts.