But when you state it like you did, there's an implication that the left hand side are the causal factors and that(Change in internal energy/accumulation) is the effect coming out of those causal factors. The problem is that there are many people with deranged metabolisms where their bodies are hormonally imbalanced to increased internal energy accumulation, which then by necessity disrupt the rest of the equation by either raising food intake or reducing energy expenditure.
(Enthalpy in) - (Enthalpy out) + (Heat/Energy crossing boundary) - (Work) - (Change in Internal Energy/Accumulation) = 0
But when you state it like you did, there's an implication that the left hand side are the causal factors and that(Change in internal energy/accumulation) is the effect coming out of those causal factors. The problem is that there are many people with deranged metabolisms where their bodies are hormonally imbalanced to increased internal energy accumulation, which then by necessity disrupt the rest of the equation by either raising food intake or reducing energy expenditure.