It's a good thing we got rid of all that sexism in the 70s

[The One and Only...]

This is potentially beneficial.

You see, fat chicks are not only harming themselves by being fat, but they are also negative externalities. By lowering the incentive to stay fat, or rather increasing the incentive to be thin, we should see an increase in the number of thin chicks over time assuming rationality among women. Thus, a decrease in the aggregate number of negative externalities.