In 1874, England increased taxes for the imported sugar, the price has fallen by half, and at the end of the nineteenth century, a part of calories in the British diet came from sugar, and the rest came mostly from refined flour.

Because of the pure and cheap sugar was now accessible to all, the human metabolism must face not only a steady flow of glucose, but also a higher amount of fructose, because sugar or sucrose is half fructose. (The consumption of fructose per capita increased by 25 percent in the last 30 years) In nature, fructose is a rare and precious element, which is found, depending on the season, in the ripe fruit, “wrapped” in a whole food product full of fibers (which slows the assimilation) and important micro-nutrients. No wonder that natural selection has programmed us to be attracted to sweet foods: in form that is found in nature-in fruits and some vegetables – sugar gives us a slow-release form of energy accompanied by minerals and all kinds of micro-nutrients essential to us that we can not get from other sources. (Even honey, the purest form of sugar met in nature, contains some micro-nutrients.)

One crucial change occurred in the American diet after 1909 (when the U.S. Department of Agriculture began to notice the phenomenon) was the increase of the percentage of sugar calories from 13 to 20%. Add to this number the percentage of calories from carbohydrates (about 40%) and it results that at least half of the American diet consists of various forms of sugars -calories which provides nothing but energy. There are two ways that the energy density of refined carbohydrates leads to obesity. First, we are consuming much more calories per unit of food, the removed fiber from the food is the one which would have give us the feeling of fullness, making us so stop eating it. Also, the sudden fluctuations of glucose drives faster to high insulin levels which, after glucose is assimilated drops sharply, creating the feeling of hunger.

If the accelerated spread of western diets has given us immediate satisfaction of sugar for many people-especially for those recently exposed to this system-the speed of this industrial diet overcomes the capacity to process insulin, the consequence being the appearance of type 2 diabetes and all other chronic diseases associated to the metabolic syndrome. As a specialist in nutrition said, “we actually participate in a national experiment of intravenous glucose administration”. And let’s not forget the flow of fructose, which might be a much higher evolutionary novelty, and therefore much more difficult to manage by the human metabolism than glucose. Probably not accidentally the rates of type 2 diabetes are lower in European populations which have had a longer period of time than other groups to adapt their metabolism to the quick release of refined carbohydrates: these changes occurred first in their food environment. The first contact with such food, as it happens in case of ordinary people who have traditional diets and come to America or if the fast-food comes to them is a shock to the body. A shock that is called by experts a nutritional transition and it can be fatal.

This is the first major change in the Western diet which may explain the devastating effects they have on people’s health, replacing the known relationships with whole foods whom we have co-evolved for thousands of years. The Western diet force our body to connect and to face some nutrients that are efficient delivered and snatched from their diet context. Our ancient evolutionary relationship with the seeds of cereals and with the fruit from plants suddenly gave up the place to a rather shaky marriage with glucose and fructose