  An updated and extended analysis of the quark mass dependence of the
nucleon's axial vector coupling constant g_A is presented in comparison with
state-of-the-art lattice QCD results. Special emphasis is placed on the role of
the Delta(1232) isobar. It is pointed out that standard chiral perturbation
theory of the pion-nucleon system at order p^4 fails to provide an
interpolation between the lattice data and the physical point. In constrast, a
version of chiral effective field theory with explicit inclusion of the
Delta(1232) proves to be successful. Detailed error analysis and convergence
tests are performed. Integrating out the Delta(1232) as an explicit degree of
freedom introduces uncontrolled errors for pion masses m_pi >~ 300 MeV.
