For nutrition labelling within the EU, either the Englyst method or AOAC method may be used for the fibre content of foods. However, these methods yield different values for the fibre content of foods. In general, the AOAC method tends to give higher values than the Englyst method, the magnitude of the difference varying between foods. This is because the Englyst method determines fibre as non-starch polysaccharides, whereas the AOAC method determines fibre as non-starch polysaccharides plus resistant starch and lignin.

Traditionally, the UK and Ireland have used the Englyst method for fibre, whereas other European countries use the AOAC method. This makes it difficult to compare fibre contents of foods produced in different countries. In the UK, the Food Standards Agency (FSA) has recommended that the AOAC fibre method now be used for nutrition labelling purposes.

The UK food composition tables only include AOAC fibre contents for a very few foods. (Fibre contents are given for the Englyst method). AOAC fibre contents are, however, available for a wide range of foods in the USA food composition tables (USDA). These data are now available for import into CARAT version 2.0 or higher.

AOAC fibre values were taken from the USDA food composition database, where a similar food exists. The mapping of foods between the UK and USDA food composition databases for fibre content was done for CARAT by a Registered Nutritionist.

There are currently about 5,000 foods in the UK food composition database. Of these, 72% have been allocated AOAC fibre values within CARAT. This compares with 86% for Englyst fibre in the UK food composition database.