Now onto the historical and anthropological reason one shoes avoid grains. First let me start by saying that our ancestors at least initially didn't consume grains. Whether you believe in the Bible or evolution if you dig far enough I'm confident you will agree with me that early mankind lived a hunter/gatherer lifestyle. This means They either killed their food or picked off trees and bushes in the form of nuts, fruits, and berries. Or they foraged for it on the ground, as in leaves and roughage, vegetables, and such. Being I believer in creation I can say that our bodies were created for this lifestyle. Notice it is also a lifestyle that perpetuates much activity, something else that is necessary for longevity and health. Contrary to a dependancy on an agricultural lifestyle which while it has some active components it also lends itself to long periods of inactivity and a lack of fresh, live foods.
Agriculture,therefore grains, didn't appear until 3 main events occured. One people stopped being quite so nomadic and could actually consistantly begin to farm a single plot of land. Urbanization began to occur, leading to the necessity of a food source that could go along way, or feed many with little. And lastly famines began to hit different civilizations forcing them to find a cheap reliable food source that was hearty and would not die out as animals and livestock would. Therefore any use of grains by ancient peoples was more of a last resort and a once in a while thing rather than a staple in their diets as it has become now. Who knows how long ancient peoples lived before the advent of agriculture and grains (again it depends on your world view) but we can safely say it was at least long enough for our bodies to function best on hunter/gatherer foods.
Furthermore let us not forget that the types of grains our ancestors consumed were significantly different than what we consume today. Firstly, the only real processing grains went through historically was to cut them from the fields take them to the mills to be ground into a whole flour with the chaff sifted out. then they were combined with natural oils to bake breads. Yeast was rarely used. Historically grains were only consumed that had gone through germination, sprouting, or fermentation. Any of these three processes nulified the phytic acid in the grains and brought out the most beneficial components of the grains. THese grains were alive. TOday unless it is a company like Good For You foods that makes live grain products like Ezekial breads, etc all based on bliblical recipes then it is best to stay away.
Dr. Carl Taylor renowned naturopathicphysician Wwhen doing a lecture in London, Ontario in 2003 held up several test tubes of grain that had been separated into it's many components. He showed that the bread he grew up on almost 65 yrs ago contained 9 out of 11 elements of a complete grain while whole wheat breads today only contain maybe only 3 0r 4 out of 11. He then sarcastically eluded to the fact that the modern day recipe for bread was white flour and water which was also the recipe for glue when he was in kindergarten. Hence the abundance of digestive issues that plague persons who eat copious amont of grain.
Don Tollman, another well sought after health lecturer talks about the book of Daniel (ch 1:8-15) and Daniels challenge to the king. Daniel wanted to prove to the king that a diet if simple, live foods (referred to as pulse) would far more improve the health of the people than a diet of rich calorically dense foods that the nobility regularly ate. After the testing period was over Daniel's men wer much stronger while the king's men suffered from many of the common ills we see today in society.
Further more not all cultures are well suited to a grain based diet which is why I think the Canada/American food guides are so shamefull. You have two countries that pride themselves on multi-culturalism; yet their dietary counseling takes a very narrow minded approach that maybe only works for a very specific demographic. For example the Inuit peoples survuve on no grains because they have virtually no growing season. Also vegetation in general (a great arguement for the anti-vegan lifestyle). It is mostly animal products with a small amount of evergreen type plants and sea vegetation. Yet they can boast about as many centurians as any other culture in the world. Yet when they are put on the typical North-American diet theyh balloon up like whales. You see every culture in the world; with their wide variety of diets can boast a great deal of people who are healthy and strong well into their hundreds and so it is sensless to argue that one ethnicity has the dietary solutions to all things. Either take a sampling from all cultures and see waht works best for you or get in touch with your own ethnic roots and do your best to mimic your great-grandparents eating habits. This is where you may find true change.
For example my ethnicity is half German; half Ukranian so I gain weight quickly with grains. I do best with mostly vegetables and lean meats and dairy. One muast keep in mind more specifically than ethnicity is the region of the country you are from. A larger country will differ quite a lot from region to region. So someone claiming to eat traditional Chinese cuisine may have drastically different views than another Chinese person.
Most Asians, Africans, and South Americans do well with grains because it has been apart of them for several thousand years. Whereas most caucasian/ European persons do better with the hunter gatherer diet.
Here is another important point. There is a huge difference between eating grains and living off them. Most people could do quite well with 40-50g per day of grain based carbohydrates yet the average person will easily consume 200-300+g of grains per day. Even if these were all live grains you would still be doing yourself a great diservice.
Here is a simple test to see how well you tolerate grains or carbs in general. When you wake up in the morning assess your energy levels and overall mood. Then prepare yourself a high carbohydrate breakfast. The typical Canadian breakfast with pancakes and maple syrup, toast and orange juice would be ideal. Then assess your energy levels and mood afterwards, say an hour later. IFyou feel lethargic, bloated, or depressed, it is safe to say you do not tolerate carbs well. However if you feel energetic and 'light' you can probably make grains a regular part of your diet without compromising your health.
If you are to eat grains it is best to eat them in the morning as your glucose tolerance is higher. Also you have the rest of the day to deal with any ill effects. Or they may be permitted after a particularly intense workout but I suggest it be a killer before you use this. THe idea being that when your body is severely taxed that it will quickly and easily utilize glucose based foods to rebuild glycogen stores in the muscles and liver.
Also the more naturally lean you are the better propensity you have for metabolizing grains well. However if you naturally carry some extra weight around or you have softer features avoiding carbs or grains in general for prolonged periods is advised.
There used to be a big difference 50 yrs ago between complex carbs and simple carbs. Now there is way too much crossover. So if you are in doubt- go without.
To me this last stat is the kicker in the no grains vs grains arguement. Back in the late eighteen and early nineteen hundreds when being a bit bigger was in vogue they had actual weight gain doctors whose entire practice was to help slender patients pack on the pounds. One of their chief recommendations was to eat breakfast cereals comprised mainly of grains. How many people do you know to today that are desperately trying to lose weight that start and end their day with a bowl of their favorite breakfast cereal.