It's good to point out that grains and soy aren't edible in nature without processing and so It's safe to assume we haven't eaten them for millions of years. Only since the advent of agriculture we started to rely on grains for our food supply. That was a huge mistake. There are several reasons why grains and soy are bad:
Grains are in fact a large supply of starch, surrounded by a kernel. Starch decomposes (digests) into maltose and isomaltose in the intestines, which then decompose into glucose. You can look at it this way. When you take a slice of bread and crush it in your hand, you are virtually eating that amount of refined sugar. The problem is that that amount of sugar elevates the bloodsugar levels amazingly fast and causes your pancreas to produce lots and lots of insulin to metabolise it. Humans are not adapted to eat such amounts of concentrated carbohydrates and the pancreas (and adrenals) aren't fit to the job. Over time one will develop insulin resistance, hypoglycemia, diabetes II. Another problem is that the immune system crashes when your bloodsugar levels increases to high levels. It takes *hours* for the the immune system to recover fully.
Another problem with refined grains is that It's void of minerals and vitamins, which are needed to properly digest and metabolise the huge amount of starch. So, each time you eat a slice of bread, your body needs to take minerals and vitamins from its limited stores to digest and metabolise it. Over time, you will develop deficincies of these vitamines and minerals.
You could eat the grains unrefined, but then a lot of antinutrients will remain. Antinutrients are substances that bind to essential vitamins and minerals, making them worthless or impossible to absorb from the digestive tract.
So, either way, refined or unrefined, grains will cause problems. Further, many grains contain a lot of allergens which upset your immune system and causes the development of allergies. Imagine this: Humans have never in their evolution of millions of years eaten grains and now, since only 4.000-10.000 years ago, we are relying on this food. Our genes aren't adapted to these foods. Grains are in fact incompatible with humans (and also dogs and cats and many mammals).
Soy beans aren't edible raw and they are full of antinutrients and substances that act like hormones in the human body. Eating soy can cause women to have menstruations that last 2 days longer than normal and are way more painfull.
Another problems with grains and soy bean it that they can't be eaten raw, which only allows us to eat them cooked. Cooking essentially damages all foods. The more you eat raw, the better you will feel.
I forgot perhaps the most important reason why grains are bad: They are very hard to digest properly. As I said above, they need to be digested in two phases.. First, the starches, which are very long chains of carbohydrate molecules, must be seperated into small pieces consisting of 2 glucose molecules. This is called maltose (or isomaltose). Next, the intestines need to produce enough enzymes (maltase) to digest the maltose into the elemental glucose molecules. As you see, quite a lot of work. The problem is that the human body isn't fit for this job and a part of the starch isn't absorbed and descends into the large intestines, feeding critters, causing inflammation, gasses, damage to the wall of the intestines, and other problems.
Compare this to fruit and honey, which are predigested foods. They primarily contain glucose and fructose, which don't need to be digested at all and can be absorbed painlessly by the intestines. Because everything is easily absorbed it can't feed the critters.
I bet there are even a dozen more reasons why grains and soy are bad but I think these are the most important.
As for the problem of not getting enough carbs: No such problem exists. Carbohydrates are optional. You can survive and feel perfectly healthy on a zero-carbohydrate diet. Look at the Eskimo's who virtually eat zero carbohydrates and look at the thousands of people eating according to a low-carbohydrate diet. They are a *lot* healthier than people eating their grains each day.
Grain Information: Dr. William Davis 11/21/2012 - Wheat: The UNhealthy Whole Grain
Grain Information: Jon Barron 11/5/2007 - The Whole Grain And Nothing But The Grain, Part 1
Grain Information: Jon Barron 11/19/2007 - The Whole Grain And Nothing But The Grain, Part 2
Grain Information: Natural News 2/27/2009 - Whole Grains Give Health
Grain Information: Natural News 3/29/2013 - The Dangerous Truth About Grains
Grain Information: Dr. Ben Balzer,M.D. - Introduction To The Paleolithic Diet
Grain Information: Dr. Mercola 6/3/2000 - Corn Dominated Diet
Grain Information: Dr. Mercola 9/24/2000 - Banned Biotech Corn Taco Bell Shells
Grain Information: Dr. Mercola 6/24/2000 - What Are We Designed To Eat?
Grain Information: Dr. Mercola 2/24/2001 - Wheat
Grain Information: Dr. Mercola 3/14/2001 - Gene-Spliced Wheat
Grain Information: Dr. Mercola 12/4/2004 Grains Part I
Grain Information: Dr. Mercola 12/4/2004 Grains Part II
Grain Information: Dr. Mercola 1/15/2005 - Sugar
Grain Information: Dr. Mercola 3/19/2005 - Wheat
Grain Information: Dr. Mercola 4/9/2005 - Wheat Bread
Grain Information: Dr. Mercola 6/30/2005 - Cataracts
Grain Information: Dr. Mercola 7/5/2005 - Competition
Grain Information: Dr. Mercola 7/16/2005 - Bread
Grain Information: Dr. Mercola 12/5/2006 - Break The Bread Trap
Grain Information: Dr. Mercola 12/12/2006 - Cooking Grains Can Poison Food
Grain Information: Dr. Mercola 12/15/2007 - Eat Grains If You Want To Go Blind
Grain Information: Dr. Mercola 7/5/2011 - Five Foods May Cause Problems VERY Similar To Wheat