Although the biodiversity crisis is well recognized, food web networks are considered little in the context of the Anthropocene because their complex structure has not been well characterized. The integrated trophic position (iTP), which is defined as a biomass-weighted average trophic position (TP) of a given food web, is a new proxy that can be measured by stable isotope analysis. To explore factors controlling the iTP, we analyzed published food web networks available at EcoBase and calculated their iTP (N = 158). All the food webs were unfolded to food chains using the Food Network Unfolding technique. We then derived three complexity indices: horizontal diversity D_H, range diversity D_R, and vertical diversity D_V from the unfolded food chains. Strongly positive correlations were found among iTP, D_R, and D_V, suggesting that iTP can be a proxy of the food chain length and the degree of omnivory. We also found that the iTP of partial communities that only consist of low TP species significantly underestimates the iTP of the total communities. It is concluded that the iTP index, which is in practice observed as the partial iTP, needs to be properly calibrated to represent the iTP of the total food web network.