There is provided a method and a system for monitoring or controlling and recording a nutritional intake of a subject comprising providing a plurality of different types of foods packaged to contain a predetermined and substantially uniform content of at least one nutritional component; and monitoring or controlling the number of food packages consumed during a predetermined time period. There is also provided a food unit and an assembly of food units for use. In addition, there is provided measuring devices for measuring at least one nutritional component of a food.