Recent studies have shown that adaptive evolution can be rapid enough to affect ecological dynamics (rapid evolution). These studies tend to focus on trait functions relating to interspecific interactions; however, the importance of rapid evolution of stoichiometric traits has been relatively overlooked. Various traits can affect the balance of elements (C, N, and P) of organisms, and multiple environmental changes may exert a selection pressure leading to adaptation of stoichiometrically important traits, such as an organism's growth rate. Rapid evolution of stoichiometric traits will not only alter population dynamics but also influence ecosystem functions such as nutrient cycling. We theoretically investigate the effects of rapid evolution of a consumer's stoichiometric P:C ratio on consumer-producer dynamics, assuming a tradeoff between the P:C ratio and growth rate based on the growth rate hypothesis. The results indicate rapid evolution of the consumer stoichiometric trait can destabilize population dynamics and may influence the level of nutrients available in the environment. Our study represents an important step for theoretical integration of rapid evolution and ecological stoichiometry.