A method and a data processing apparatus for selecting a food product based on the food product&rsquo；s health effect on a human being are disclosed. The data processing apparatus comprises (a) a data gathering device, b) a computer module for associating the first and the second food products with a metagroup, c) a computer module for calculating a first healthfulness data for the first food product； d) a computer module for calculating a second healthfulness data for the second food； (e) a computer module for comparing the first healthfulness data to the second healthfulness data via the processor of the data processing apparatus； and (f) a computer module for providing an outcome of the comparing step which is display on a presentation device of the data processing apparatus product. The data gathering device is substantially designed to (i) obtaining data about nutrients of a first food product, and (ii) obtaining data about nutrients of a second food product； The metagroup is determined based at least, in part, on: i) a similarity in nutrients among different food products, and ii) similarity in usage of different food products within context of a specific diet and the metagroup is associated with a specific healthfulness formula stored in a storage device of the data processing apparatus. The healthfulness formula is a linear combination of at least a plurality of the following data about nutrients of a food product: i) fat content, ii) sugar content, iii) sodium content, iv) energy, v) saturated fat, and vi) dietary fibre content. The first healthfulness data for the first food product is calculated based on the healthfulness formula of the metagroup via the processor of the data processing apparatus. The second healthfulness data for the second food product is calculated based on the healthfulness formula of the metagroup via the processor of the data processing apparatus. .
