The standard dynamic energy budget model has no plausible alternatives

During its 40 years of development, the assumptions of the Dynamic Energy Budget (DEB) theory for metabolic organisation turned out hard to replace. To understand this, a reasoning is here presented for why its standard model has no alternatives with a comparable level of simplicity and will never have them. Energy and mass conservation rules are essential to quantify the eco-physiological development of an individual organism thermodynamically. These rules strongly constrain the mathematical modelling of this development. In combination with consistency with a small set of stylised empirical facts, the freedom of modelling the skeleton of the model is reduced to a single one: the standard DEB model. This skeleton can, however, be extended in many different ways to capture particular 'details'. The key-message of this paper is that the more simple metabolic models become, the more constraining are consistency conditions.