Since this is either getting downvoted by people getting upset by the joke or people not getting it I will explain the joke.
Unhealthy points to the big bodied people or BBW BBM. Generally people who are obese or unhealthy.
So they have an "Unhealthy" attraction.
I have seen blatantly offensive for the sake of offensiveness jokes get downvoted less so either way the joke and the reaction to the post makes me laugh.
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