Basic Theory of the SCD Diet
The theory of the SCDiet is explained in Chapter 4 of Breaking the Vicious Cycle (May 2010 edition).
To put it in the simplest terms, digestion is supposed to be completed in our small intestine through the action of digestive enzymes. When this does not properly occur for whatever reason, nutrients enter the large intestine (colon) and feed the many types of bacteria there.
The SCDiet recognizes that we each have control over what we put into our digestive system. The SCDiet is a selection of delicious foods that nourish us but require minimal internal processing. This ensures that digestion is completed in the small intestine and nutrients are not entering the colon.
This allows the intestines to heal overtime.