Fasting Mimicking Diet Part 2

Aaron Hartman, MD explains that a fasting mimicking diet aims to reproduce the ketone production and detoxification benefits of fasting while allowing food intake. He contrasts this with interval (intermittent) fasting — typically 16–18 hours daily — which produces low-grade ketosis. He describes a metabolic timeline: the body uses sugar for energy for about 4–6 hours, transitions to glycogen then exhausts glycogen around ~12 hours, and ketone production begins after glycogen depletion. He also notes that frequent snacking or high carbohydrate intake can prevent timely switching and cause symptoms (jitters, 'hangry') around the ~4-hour mark.
Questions this video answers
Typically 16–18 hours daily (Monday through Friday).
About 4–6 hours.
Roughly around 12 hours (glycogen run-through ≈12 hours), after which ketone production starts.
Jitters and feeling 'hangry' due to failure to switch from sugar-based to fat-based metabolism.










