It's not really so much a matter of when autophagy kicks in as when it peaks. There's always some going on. Peak autophagy claims are a little problematic, when we get into even micrograms of protein 'shutting down' autophagy--that gets into autophagy in cell cultures, where levels of amino acids etc. can be brought down lower than they normally would ever get to in a living body. Compared to the sort of spike you'll see in that very stressful condition, normal physiological levels of autophagy can look sort of tepid--even if they are actually relevant, over time, to health.