That won't happen, attraction and our concept of beauty is not learnt or a "social construct", like some fat-fats claim. Rather there are very strong evolotionary pressures for us to favour fit, healthy mates as they are better suited to produce and care for young, thus giving the best chances that your genes make it to the next generation. That has been selected for in our evolutionary psychology.  It's the same with things like symmetrical faces and other metrics of beauty. For example robust genes lead to symmetry, robust genes means strong progeny, so people who find this attractive come to dominate as they're always mating with the good genes.  Of course there is always variation within the population. So you get stuff like fat fetishes and stuff. But this is the general rule and is here to stay. TL;DR our evolution up to this point pretty much guarantees that the fat acceptance bullshit is doomed to fail.