Cooking is processing too, and does indeed cause some nutritional loss. Its benefit however outweighs that (for e.g. cooked food is tastier, we are able to digest cooked faster and better, thereby expending less energy for it), and we also compensate for the loss of nutrition by consuming different food at the same time (having created recipes with different basic food groups, and what is now popular and promoted as the 'balanced diet'). I was however particularly referring more to processing wheat flour to refined white flour, from which white bread is made. These food products are optimised for taste rather than nutritional value. The more you refine it, the more likely you are to strip some nutritions from it. For example, here is how modern refined white flour is made in many parts of the world - https://food.ndtv.com/food-drinks/how-is-maida-made-and-is-i... . That aspect also matters today when you compare it past food habits and food processing - today, we refine many food products more than we used to do in the past. (And apparently, we are now even growing with food with less nutritional values, because we are prioritising and optimising more for how the produce should look - https://www.nationalgeographic.com/magazine/article/fruits-a... !)
