why lunch at noon?
well, ds is my oldest and he did clockwork routine was obviously the child GF based her book on
milk every 3 hours, 7, 10, 1, 4, 1, 10.
When we started weaning, we introduced some food at 12, before starving for milk, he ate, then afterwards topped up with his 1 pm milk. Over time the top up milk was dropped, and he had lunch at 12. He is such a person of rigid routine (didn't realise how much till laid back dd1 arrived) that by 12:15 he was starving and by 12:30 past eating as he had 'missed' his lunch time.
As he got older we did push lunch back to our more normal 1 pm.
I know lots of people for whom 5-5:30 is normal evening meal time. In fact if you ask, many of those people call their evening meal tea, while those who eat later call it dinner, and it is all hang over from class past.
(non working people had afternoon tea at 4 and dinner at 7, while working class had hot meal at 5-5:30 after work. Farmers often came in for hot meal and then went back out again to work, and then had supper before bed).