What really happens inside your organs during a 36-hour fast? Hour by hour, your body shifts from sugar-burning mode to fat-powered efficiency. Your liver drains its stored fuel. Your brain switches to ketones. Your cells activate internal cleanup systems. And by hour 36, your metabolism is operating on an entirely different energy strategy. #fast #fasting #science #weightloss #intermittentfasting #bellyfat #food 00:00:00 The first hours without food (0–6h) 00:00:55 Hours 6–12 — Glycogen down, fats stir 00:01:46 Hours 12–24 — New sugar and rising fat fuel 00:02:50 Hours 24-30 — Ketones take the stage 00:03:53 Hours 30-36 — Clean burn, organ tour, electrolytes 00:05:02 Summary of roles — the organ symphony 00:06:09 Common feelings, signs, and simple tips 00:07:07 A final note — who should not fast; how to break safely