I agree with the OP's claim that we are mostly socialised into viewing fat people as ugly. I think it reflects the overabundance of food and the prominence of obesity in contemporary society.
Depictions of plump nude women characteristic of the premodern era, underline how bodily norms are dependent on the nature of our social context. In those times, a weighty figure was considered desirable amongst the upper classes, despite the fact that poverty was relatively prevalent. In contrast to today, obesity was rare and was an indication of wealth and high social status.
This contradicts the view that we are somehow biologically predisposed to be attracted to athletic bodies. Whilst I wont completely discount that there is some truth to it, IMO, our biological predispositions are overwhelmed by the values, beliefs and norms we pick up from everyday experience and our social surroundings. Human beings are learning creatures - this is what distinguishes us from animals. Our unique capacity for learning and adaptation makes it possible for us to overcome our genetic limitations.







