>>14121781a diverse range of sexual attraction allows a population to keep a diverse range of traits. While fatness isn't currently advantageous at all, it could potentially be advantageous in the future. Therefore it's beneficial for the population to have a small number of people attracted to that trait, so that if it becomes advantageous in the future those people can propagate that trait. A population can only evolve in a certain direction if there's members of that population willing to produce offspring with those traits.
