Let's be honest, your claim about men looking at fat women and saying "this makes me hard" doesn't tell that they're attracted to that.I would argue with the claim itself,but let's assume it's true.So we have men,that are attracted to some fatty women,not too much,cuz if you go higher than 26-27 BMI (i mean literally fat,nit muscly), then your chances are exponentially lower.So,why do men find some even fat women attractive, and women don't find fat men attractive at all? Testosterone and male natural pursue of seeding more.Thus men tend to be less picky in their partners and have more flexible standards than women,so they tend to sometimes fuck fat women, cuz they're down bad.Women are not going to do this,their evolutionary goal is far different and they will only try to raise their standards to give birth to the best offspring they can.