Whole grains, wheat, barley, rye and oats contain gluten. Gluten is a protein. The protein is like a long chain of amino acids, its like a string of pearls, it is the stomachs job is to break down the string of pearls, to liberate the amino acids, which are essential nutrients. But the chemical bonds which hold the amino acids of gluten together, are really really difficult for most people's stomach acids to break. So if you eat a whole wheat sandwich, you chew it up, you swallow it, it goes down into your stomach, the acid in your stomach tries to break the string of pearls of the protein in the gluten, but it can't do it. So now, instead of individual amino acids tumbling through the small intestines, which is the next stage of digestion, you get these big complicated architectural strings of protein; undigested protein. Now your small intestines job is to absorb the nutrients that your stomach has just turned into liquid into the bloodstream, and your small intestine d...