  Several models have been advanced to explain the multiple stellar populations
observed in globular clusters (GCs). Most models necessitate a large initial
population of unenriched stars that provide the pollution for an enriched
population, and which are subsequently lost from the cluster. This scenario
generally requires clusters to lose $>90$ per cent of their birth mass. We use
a suite of 25 cosmological zoom-in simulations of present-day Milky Way-mass
galaxies from the \emosaics project to study whether dynamical disruption by
evaporation and tidal shocking provides the necessary mass loss. We find that
GCs with present-day masses $M>10^5~M_{\odot}$ were only $2$-$4$ times more
massive at birth, in conflict with the requirements of the proposed models.
This factor correlates weakly with metallicity, gas pressure at birth, or
galactocentric radius, but increases towards lower GC masses. To reconcile our
results with observational data, either an unphysically steep cluster mass-size
relation must be assumed, or the initial enriched fractions must be similar to
their present values. We provide the required relation between the initial
enriched fraction and cluster mass. Dynamical cluster mass loss cannot
reproduce the high observed enriched fractions nor their trend with cluster
mass.

Astrophysics of Galaxies