1. A system for the remote monitoring of food intake and physical activity in a subject, comprising: a) a device configured to be worn on a subject for the remote monitoring of food intake and physical activity in a subject, comprising: a housing; a bus inside the housing; one or more sensors connected to the bus; two or more imaging sensors connected to the bus and positioned in the housing to record a stereo image; an eating detector in the housing and connected to the bus, eating detector comprising a light beam source configured in the device to pass a light beam in front of a subject's mouth when the device is worn by a subject and a light sensor able to measure changes of light intensity in a path of a light beam from the light beam source; a microprocessor connected to the bus; a data storage device connected to the bus and comprising a data storage medium; a program for managing one or more operations of the device including imaging, data acquisition and storage; and a power supply connected to the bus; b) a computer; and c) a data communication interface for transferring data between the device and the computer, wherein one or both of the device and the computer comprises one or more programs for determining a dimension of a food item in image data obtained from the imaging sensors and determining a physical activity of a subject wearing the device.