Lockdowns are enough.

People WILL comply because they think this had a realistically survivable time frame and countries who enforce lockdowns will use their armies (ensuring people will not oppose them), and the emotional toll will be so severe that after a decade many people WILL choose death.

And had you heard of the Mice Utopia experiment? It doesn't even need a starvation crisis. If they grid lock you for a given amount of time you WILL become insane.