  Motivated by our recent work relating canonical bases to combinatorics of
Garsia-Procesi modules \cite{B}, we give an insertion algorithm that computes
the catabolizability of the insertion tableau of a standard word. This allows
us to characterize catabolizability as the statistic on words invariant under
Knuth transformations, certain (co)rotations, and a new operation called a
catabolism transformation. We also prove a Greene's Theorem-like
characterization of catabolizability, and a result about how cocyclage changes
catabolizability, strengthening a similar result in \cite{SW}.
