Most people don't ever stop to question why what they see as attractive is so. It just is. It's law. Tiny waist, slim legs, round breasts... That's what's naturally attractive right? Wrong. In today's culture there is no such thing as 'naturally attractive'. We are all brainwashed into buying the 'ideal' body of the times and most of us don't even realise it.
The figures of the women in the painting were idolised because bigger meant more food, more food meant more money, the higher class could be recognised and glorified by their body types. Until food became more readily available to the masses, then they needed a new way to distinguish themselves - thin was in.
A while later after women became disenchanted with their roles as housewives after working in war factories, the patriarchal beast that is the retail industry realised they couldn't cash in on home products anymore to take women's pocket money and abuse their time. They needed a new financial and social restraint. The diet, beauty, and fashion industries are multi billion pound restraints on women. They are ever changing, you will never reach the 'ideal' they are currently selling because if you come close they change that ideal so their industries continue to flourish and women continue to be controlled.
So we can either buy into it all and spend our lives in chains chasing the unattainable physical perfection of today, or we can just be ourselves, and not let society fuck us up.