ABSTRACT. – Trophic enrichment factors (TEF) are essential to properly and fruitfully explore stable isotope analysis in ecology. And so is the time window of food source integration, usually estimated with the turnover rates (λ) of isotopic incorporation. On the road to provide ecologists with a general and reliable method to obtain TEF and turnover rates for diet reconstruction, isotopists start realizing that those two parameters are ultimately linked with the physiological state of organisms and that metabolic pathways are of primary importance to understand the large ranges in TEF values. In this study, we used a diet-switching experiment for seven small marine invertebrates. Changes in isotopic compositions were fitted to an exponential decay model to estimate TEF and λ values. We then partitioned the growth and the catabolism components of the turnover rate and tested how these components are correlated to the TEF among species. Results showed a significant linear negative relationship between TEF and growth values for both C and N. This ultimately means that the increase in body mass over a time window can be used to estimate the TEF values for a given species