Atwater system

The Atwater system, named after Wilbur Olin Atwater, or derivatives of this system are used for the calculation of the available energy of foods.

The system was developed largely from the experimental studies of Atwater and his colleagues in the later part of the 19th century and the early years of the 20th at Wesleyan University in Middletown, Connecticut. Its use has frequently been the cause of dispute, but few alternatives have been proposed.

As with the calculation of protein from total nitrogen, the Atwater system is a convention and its limitations can be seen in its derivation.

Source: https://en.wikipedia.org/wiki/Atwater_system