The Specific Carbohydrate Diet (SCD) is promoted as for the treatment of a number of chronic illnesses, mainly those of an auto-immune nature. Illnesses which the SCD has been used for include Crohn's disease, ulcerative colitis (UC), diverticulitis, autism, irritable bowel syndrome (IBS), celiac disease, Candida overgrowth, and many more.
The main dictates of the SCD are that the patient eliminate complex carbohydrates (disaccharides and polysaccharides) as well as lactose above a significant amount.
The diet was originally developed by Dr. Sydney Haas but was popularized by Elaine Gottschall's book Breaking the Vicious Cycle. Gottschall was inspired to write the book and promote the diet after her own daughter's successful management of ulcerative colitis using the SCD.
According to Breaking the Vicious Cycle the rationale of the diet is as follows:
- When the body receives complex carbohydrates (disaccharides or polysaccharides) these substances must be broken down before they can be absorbed.
- In the body of a person who is not able to break these substances down efficiently, an influx of undigested material causes harmful bacteria to flourish.
- Bacterial overgrowth is accordingly followed by a significant increase in the waste and other irritants they produce.
- Irritation in the lining of the digestive tract results in the overproduction of mucus and injury to the digestive tract, which in turn causes malabsorption and makes it even more difficult to maintain proper digestion.
The purpose of the diet is to break the ongoing cycle caused by an overgrowth of harmful bacteria in the gut, a condition well known to researchers as small intestinal bacterial overgrowth (SIBO). The SCD assumes that the body is able to absorb the proper nutrients from simple sugars and other easily carbohydrates, the inflammation and other complications caused by many auto-immune diseases can be lessened. The goal is to rid the body of complex saccharides so that the gut will be able to heal itself and enable further healing to occur.
The aim of the diet therefore is to keep the gut flora in balance and to allow the gut to digest all of the food it is given, thereby starving out the harmful bacteria.
The Specific Carbohydrate Diet is similar to the the anti-fungal diet but allows foods containing simple sugars such as fruits as well as fermented foods such as cheese, which the latter does not. Both have similar aims and are often recommended or the same conditions.