  The degree of mass loss, i.e. the fraction of stars lost by globular
clusters, and specifically by their different populations, is still poorly
understood. Many scenarios of the formation of multiple stellar populations,
especially the ones involving self-enrichment, assume that the first generation
(FG) was more massive at birth than now to reproduce the current mass of the
second generation (SG). This assumption implies that, during their long-term
evolution, clusters lose around $90\%$ of the FG. We have tested whether such
strong mass loss could take place in a massive globular cluster orbiting the
Milky Way at $4\ {\rm kpc}$ from the centre and composed of two generations. We
perform a series of $N$-body simulations for ${12\ \rm Gyr}$ to probe the
parameter space of internal cluster properties. We have derived that, for an
extended FG and a low-mass second one, the cluster loses almost $98\%$ of its
initial FG mass and the cluster mass can be as much as 20 times lower after a
Hubble time. Furthermore, under these conditions, the derived fraction of SG
stars, $f_{\rm enriched}$, falls in the range occupied by observed clusters of
similar mass ($\sim 0.6-0.8$). In general, the parameters that affect the most
the degree of mass loss are the presence or not of primordial segregation, the
depth of the central potential, $W_{0,FG}$, the initial mass of the SG,
$M^{ini}_{SG}$, and the initial half-mass radius of the SG, $r_{h,SG}$. Higher
$M^{ini}_{SG}$ have not been found to imply higher final $f_{\rm enriched}$ due
to the deeper cluster potential well which slows down mass loss.
