Atwater system
Assumptions based on the use of carbohydrates by difference and the effects of dietary fibre

The unavailable carbohydrates (dietary fibre) are degraded to a variable extent in the large bowel. The products of this microbial digestion are fatty acids, CO (carbon dioxide), methane and hydrogen. The fatty acids (acetate, butyrate and propionate) are absorbed in the large intestine and provide some metabolisable energy. The extent of degradation depends on the source of the dietary fibre (its composition and state of division), and the individual consuming the dietary fibre. There is insufficient data to give firm guidance on the energy available from this source.
combination:two_responses, keywords:letter_frequency, language:response_language[French]