Diet evaluation gastric apparatus (18) is provided, which detects when a
patient (10) swallows, and detects the type and amount of matter
ingested. The apparatus includes electrodes (74, 100) adapted to be
coupled to the fundus and antrum of the patient and to measure electrical
and mechanical activity therein, and a control unit (90) to analyze such
electrical and mechanical activity and optionally apply electrical energy
to modify the activity of tissue of the patient.