Correction:
Pink bar is the pleasure it takes to cum. Cum three times and you're cooked, my G.
The actual effect the anaphrodisiac has is to lower libido, so it technically still lowers lust. But the Lust is the heart icon and its percentage, not the pink bar! Remember how the heart is originally blue? That's because the playable character wasn't aroused, so she wasn't actually getting pleasure, i.e. getting closer to a climax, i.e. filling that pink bar. The heart (arousal) is a danger when pink or red.
My only lust related gripe is that I can't seem to lower the pink bar itself, so it's riskier to have filled.
On the topic of the three colored bars, the buffout to raise resistance effectivity (orange bar) is disappointingly weak.