alt Hacker NewsWhite flour has a slightly higher protein content (e.g. I bake bread from flour with 13% protein), but the important difference is that it is much cheaper, e.g. at least twice cheaper than whole wheat flour.
The reason for the price difference is unlikely to be due to a more expensive processing technology, but mostly from the economies of large scale processing, because the production of white flour is much greater.
Whole wheat flour has slightly higher amounts of the more valuable nutrients, but due to its high price it is an inefficient way to get those nutrients. A both cheaper and healthier diet can include white bread and larger amounts of other vegetables that are better sources of fiber, vitamins and minerals than whole wheat flour. (E.g. the food that I cook usually includes ingredients like lentils, carrots, parsnips, onions or garlic, broccoli or cauliflower, bell peppers, parsley or dill etc. Spending less on those in order to make more expensive whole wheat bread would provide much less desirable nutrients, so it would be a bad allocation of funds.)
Replies
No, it has nothing to do with economies of scale.
Grains contain both starch and oil and when you mill the grains, the oil goes rancid much faster than the starch.
If you remove the oil you have a nutritionally worse product but it lasts longer on the shelves.
That highlights the oddity of your calculations. You say that wheat is cheaper, but little about why. If the economies of large scale processing makes more processed wheat cheaper than less processed wheat, then maybe something else would be cheaper if our habits were different. So it's dubious to use the cheapness of white flour to argue that we should eat more white flour products.