Look, there is no denying of the impact grains had on the development of civilization.
But on the other hand what AC said is also true. I went through the whole thing - a decade of suffering until I was told to stop eating grains. I am not gluten intolerant or something like that. Now, the story of course is way more complicated than it sounds. Why could I eat grains for 30 years and then suddenly I could not? My gut flora is terribly out of balance. What caused it? According to the medics I did not give them [gut bugs of all kinds] enough job by always eating stuff that gets processed in the small intestine. Too much sugar. Too much easy carbs in general [grain]. So, If I want to be healthy and productive at the moment grains are forbidden. Every few weeks I experiment once a day to see if I can process them again. So far the result is negative [one year on the diet]. This makes my life very difficult and expensive, but there it is...
Last point - once I started paying attention to all this and talk to people I discovered that almost anyone around me is in a certain stage of the downwind spiral of imbalanced gut. People do not realize that the feeling of tiredness, too much gas, bloated gut, compromised immune system, joint pain and god knows what else can be traced to the performance of their guts [60% of immune system response is from the gut]. Whether it is eating too much carbs, or too much E numbers, or toxic metals or lack of minerals in food due to accelerated growth practices, too much sugar ...ect. all those things push a bit until your system is out of balance and you are fucked. That is why I am in principle against even more experimenting with food - we already have many bad practices and many bad habits. The natural food pyramid has easy carbs at the top [least available]; the food habits of the modern civilization has the piramyd inverted [mortal fear from fats;extremely stupid idea BTW and carbs, carbs, carbs..].
Don't forget that stomach cancer is on the rise consistently in the developed world and that regions in the world who are adopting the western food habits experience increase in obesity, diabetes and cancer. It really is like this - ATM the Arab world, China, Latin America - they are all on the rise.