Abstract: A total 134 food items were selected from Japanese Food Composition Table (FCT), and recalculated the energy values by 5 different food energy conversion systems respectively. The comparison on means, data profile plots, and analyses on absolute and relative difference (bias) all indicate that (1) different energy systems may produce significant differences on energy value, especially to high dietary fiber (DF) foods; (2) the ME specific and ME mod have showed the best correlation and consistency among systems, and produced the moderate energy values; Atwater’ factors inclined to assign the highest energy values, while the NME and European general factors have obtained the lowest energy level; (3) the Chinese FCT applied, so called European General Factors System may have underestimated the energy value on total FCT level, and have greatly underestimate the energy value when meets the very high fiber foods and diets. (4) Totally, Energy of China applied system is less (population mean and 95% CI) 36.2 (17.9～54.5) %, 17.8 (9.5～26.2) %, 17.6(8.9～26.1) % and 7.5(1.2～13.9) % than Atwater’s, ME specific, ME mod and NME respectively.

Key words: food energy conversion systems, energy factors, energy value, FCT, statistical appraisal