Wednesday, March 18, 2009

Food Energy – Methods of Analysis and Conversion Factors

In 2001, FAO, WHO and the United Nations University (UNU) convened an Expert Consultation on Energy in Human Nutrition, which provided the most recent review of requirements and other energyrelated topics (FAO, 2004). As part of the preparatory process for both the Joint FAO/WHO/UNU Expert Consultation on Energy and that on Protein and Amino Acids in Human Nutrition five working groups were created and convened in June 2001 to deal with various topics that required a more thorough review than the others. Working Group 5 was devoted to Analytical Issues in Food Energy and Composition: Energy in Food Labelling, including Regulatory and Trade Issues (see Annex II), and was created partially in anticipation of possible changes in the energy requirements that may have resulted from the new requirements being based totally on energy expenditure data.2 In addition to discussing the preferred methods of protein, fat, carbohydrate and dietary fibre analysis, Working Group 5 also considered the following in its deliberations: 1) the routes of energy loss from the body such that the lost energy cannot contribute to maintaining energy balance; 2) the size of the energy loss for each of the energy-providing substrates, including fermentable carbohydrate; 3) variations in the energy losses reported in different studies of food components; 4) energy losses from normally consumed foods that have not previously been taken into account; and 5) factors external to food energy availability that modulate energy needs and the ability to maintain energy balance. Taking all of these into consideration, possible approaches to energy evaluation, including ways to account for diet-induced thermogenesis, were discussed. At about this time, the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) requested FAO’s assistance in harmonizing energy conversion factors, and thus enabling uniformity in labelling and in the information provided to consumers (CCNFSDU, 2001a; 2002). This request was reinforced by the introduction of the information paper by the Australian delegation at the 23rd CCNGSDU session in 2001 (CCNFSDU, 2001b).


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