“…Inertia: arm, hand-to-mouth, jaw movement (bite detection), physical activity Five force-sensitive resistors (100) Pressure Heart rate monitor (patch-type sensor or built-in smartphone/ smartwatch) (86) , photoplethysmography (107) , electrocardiogram (95) , ventilation sensor (96) Physiological: cardiovascular parameters mainly heart rate, ventilation Piezoelectric sensor (56,60,70,97) , electromyography (EMG) electrodes (temporal muscle activity during mastication) (58,60,64) Swallowing movement (jaw and skin), chewing cycle and food type Global positioning system (GPS) (52,87) Location Image recognition Video recorder (63,68) Images of food item/group/type Camera (34,66,67,74,78,79,93,94) Images of food size, shape, colour, portion and texture Sound recognition Ear microphone (worn on one's inner ear, outer ear, wrist, neck near the jaw/throat) (58,59,69,71,73) Chewing sound (bone-conducted food breakdown sounds) Speech recognition Microphone (smartphone in-build microphone) (75) Verbal food description or nutrition label Wireless signal recognition Signal receiver (109) Wireless signals neighbour (n 5) (86,85,88,91,103) , clustering (n 1) (106) and support vector machines (n 14) (60,68,…”