Dynamic energy budget theory presents a quantitative framework of metabolic organization common to all life forms, which could help to understand evolution of metabolic organization since the origin of life. As such, it has a common aim with the other widely used metabolic theory: the West-Brown-Enquist (WBE) metabolic theory of ecology, which prompted side-by-side analysis of the two approaches. Though the two theories can be regarded as complementary to an extent, they were built on different assumptions and have different scope of applicability. In addition to a more general applicability, the DEB theory does not suffer from consistency issues pointed out for the WBE theory.