WHAT IS THE SPECIFIC CARBOHYDRATE DIET? SCD is the autism diet that is in accord with the latest scientific findings. Research confirms that gut pathogens (the microorganisms in the gut) cause digestive and brain problems. This research has established that gut pathogens can damage the GI tract and impair the brain function of autistic children. It attests that harmful gut pathogens survive because they feed and thrive on carbohydrates that are difficult to digest.