What is the strongest proof we have to determine attraction back then ?

People always say “well in the past fat bodies were attractive, look at Rubens, look at ancient statues.” But I’m wondering what actual evidence we have for that. Sculptures and paintings tell us what artists made, not necessarily what average people desired.

Do we have any textual, psychological, or neurological proof that people genuinely found larger bodies attractive in everyday life. Attraction involves neuroplasticity, but how much can society really rewire it. I am NOT talking about wealth I am talking about ATTRACTION, I mean I must assume people back then could think about other things than money and the high class. Can a whole population be conditioned to completely change their sexual attraction.

Basically, what is the strongest real evidence we have for what people actually liked back then. Besides art, do we have anything that shows how ordinary people reacted to different body types. Or are we projecting modern interpretations onto a few famous artworks, do we have any other proof that fat people were genuinely the visual peak during most of history ?