fasting and CR [calorie restriction] are the most potent non-genetic autophagy stimulators, and lack the undesirable side effects associated with alternative interventions.

We conclude that both fasting and CR have a role in the upregulation of autophagy, the evidence overwhelmingly suggesting that autophagy is induced in a wide variety of tissues and organs in response to food deprivation

From: https://pubmed.ncbi.nlm.nih.gov/30172870/