The reasoning: a reservoir, a grinder and a duodenal controller
- Proximal stomach: receptive relaxation (swallow‑triggered) and accommodation (vagovagal, nitrergic) store the meal at low pressure.
- Antral pump: 3/min peristaltic contractions grind solids; terminal antral contraction with pyloric closure causes retropulsion; particles ≲ 1–2 mm pass.
- Duodenal feedback: acid, fat (CCK), hyperosmolality, energy density and distension slow emptying via the enterogastric reflex and hormones (CCK, secretin, GIP, GLP‑1, PYY — "ileal brake"). Caloric delivery to the duodenum is held near ~2–3 kcal/min.