If you read Farmer Boy, you will see a vast difference in the way the Wilders grew up compared to the Ingalls'. The Wilders were prosperous farmers. The Ingalls' struggled to make a living constantly. Take breakfast, for instance.
Almanzo opened his eyes again, and the candle was sputtering on the bureau. Royal was dressing. His breath froze white in the air. The candlelight was dim, as though the darkness were trying to put it out.
Suddenly, Royal was gone, the candle was not there, and Mother was calling from the foot of the stairs.
"Almanzo! What's the matter? Be you sick? It's five o'clock!"
He crawled out, shivering. He pulled on his trousers and waist, and ran downstairs to button up by the kitchen stove. Father and Royal had gone to the barns. Almanzo took the milk-pails and hurried out. The night seemed very large and still, and the stars sparkled like frost in the black sky.
When the chores were done and he came back with Father and Royal to the warm kitchen, breakfast was almost ready. How good it smelled! Mother was frying pancakes, and the big blue platter, keeping hot on the stove's hearth, was full of plump brown sausage cakes in their brown gravy.
Almanzo washed as quickly as he could, and combed his hair. As soon as Mother finished straining the milk, they all sat down and Father asked the blessing for breakfast.
There was oatmeal with plenty of thick cream and maple sugar. There were fried potatoes, and the golden buckwheat cakes, as many as Almanzo wanted to eat, with sausages and gravy or with butter and maple syrup. There were preserves and jams and jellies and doughnuts. But best of all Almanzo liked the spicy apple pie, with its thick, rich juice and its crumbly crust. He ate two big wedges of the pie.
Taken from Farmer Boy in the chapter entitled Winter Night
What a meal! Can you imagine the nap you'd need after a breakfast like that? Why do you suppose they could eat so much at breakfast?
I think it had to do with the hard work they did. Earlier in the chapter, it's also mentioned that the temperature was 40 below zero. 40 below! They needed plenty of nutrition to keep them going with such cold temperatures and hard work. Father worked outdoors or in the barns much of the day, and Mother worked in the attic spinning wool, making candles, and doing other various chores. The children all walked to school. A breakfast like the one above would certainly sustain them!
I hope my children don't remember the part about apple pie at breakfast. I distinctly remember saying several times, "We don't have dessert at breakfast" after requests for candy, brownies, or ice cream in the morning. Almanzo was a lucky boy!