I don’t think it’s the amount of food that you eat; it’s the quality.
They had better food, back then. And they also moved around a lot more. The physical labor necessary to get through the day was greater for most people then, than it is today.
YES...to everything you wrote. BUT, I’m transcribing a diary from 1920 of family on an orchard...good lawd...they ate lots of pies, puddings, and other carbs...at least my husband’s family...and no weight problems there either. But, they did have good meat/poultry, milk, butter, etc. Not a lot of veggies, though. I do think their “movement” counted for a lot.