This is a false assumption as it ignores several mechanisms behind the riots themselves.

A better conclusion would be "rising food prices make riots easier to incite". The reason for the false assumption is the notion that the Arab Spring was largely leaderless or organic; it was not.

Most of the Arab Spring protests were encouraged and incited by the Muslim Brotherhood. The crippled economies were an excellent motivator for people to take to the streets - they did, after all, not have any work to do.

However, food prices were only a small piece of the puzzle that made the countries ripe for unrest. Many other components helped it along, including our country's naive actions.