For a Liouville domain W whose boundary admits a periodic Reeb flow, we can consider the connected component [τ ] ∈ π0(Symp c ( W )) of fibered twists. In this paper, we investigate an entropy-type invariant, called the slow volume growth, of the component [τ ] and give a uniform lower bound of the growth using wrapped Floer homology. We also show that [τ ] has infinite order in π0(Symp c ( W )) if there is an admissible Lagrangian L in W whose wrapped Floer homology is infinite dimensional.We apply our results to fibered twists coming from the Milnor fibers of A k -type singularities and complements of a symplectic hypersurface in a real symplectic manifold. They admit so-called real Lagrangians, and we can explicitly compute wrapped Floer homology groups using a version of Morse-Bott spectral sequences.