The traditional food pyramid as we known is a bit wrong because it says that we must eat cereals and pasta but this is not true. The homo sapiens are not used to consume this things, we havent been in the Earth enough time. This table shows very well this:
8,000-10,000 years ago, man learned to become a farmer, and with it he began to consume cereals in significant quantities. At the same time, we also learned to domesticate animals, which gave us access to new foods, such as milk and its derivatives.
We take 1% of our existence taking these products so in some populations we are not able to process these foods correctly.
This does not mean that we necessarily eliminate these foods, but it is reasonable to think that they should not represent a large part of our food.
With the industrial revolution, food is processed and produced in large quantities. Since the industrial revolution, the production of refined sugar is massified and its consumption begins to increase exponentially.
Before, to take the sugar equivalent of a Coke you had to spend several days chewing sugar cane. Today you can take it in 5 minutes.
But now there are also alternatives to sugar that are as bad as sugar. Also almost all the cereals and flour are processed like the milk that in any case we should take it whole
Our health has worsened with the emergence of new diseases such as cancer, diabetes or obesity, and the main factor is food.
If you want strong health, make sure that most of your food is similar to that of a hunter-gatherer, with moderate amounts of dairy and cereals, and almost eliminating the processed products.