When you stop eating, your body does not simply wait for food. It flips three switches in sequence. First, the insulin drop, four to eight hours in: when insulin falls, your fat cells unlock. You literally cannot burn stored body fat while insulin is elevated — which is why constant snacking prevents fat loss regardless of calories.

Second, the ketone rise at twelve to sixteen hours: your liver converts fatty acids into ketone bodies, an alternative fuel your brain actually prefers. Ketones are anti-inflammatory and appetite-suppressing, which is why hunger often disappears at the 14–16 hour mark rather than increasing. Third, autophagy at sixteen to eighteen hours: your cells begin recycling damaged components — the maintenance system that only runs when you are not eating…