In the 1960s, Curtis Dohan speculated that the low incidence of schizophrenia in certain South Pacific Island societies was a result of a diet low in wheat and milk-based foods. Dohan proposed a genetic defect wherein individuals are incapable of completely metabolizing<unk>  and<unk>  as a possible cause for schizophrenia. Dohan hypothesized that elevated peptide levels from this incomplete metabolism could be responsible for schizophrenic behaviors. In 1979, Jaak Panksepp proposed a connection between autism and opiates, noting that injections of minute quantities of opiates in young laboratory animals induce symptoms similar to those observed among autistic children. The possibility of a relationship between autism and the consumption of<unk>  and<unk>  was first articulated by Kalle Reichelt in 1991. Based on studies showing correlation between autism, schizophrenia, and increased urinary peptide levels, Reichelt hypothesized that some of these peptides may have an opiate effect. This led to the development of the Opioid excess theory, expounded by Paul Shattock and others, which speculates that peptides with opioid activity cross into the bloodstream from the lumen of the intestine, and then into the brain. These peptides were speculated to arise from incomplete digestion of certain foods, in particular<unk>  from wheat and certain other cereals and from<unk>  from milk and dairy produce. Further work confirmed opioid peptides such as casomorphines (from<unk>  and<unk>  exorphines and gliadorphin (from<unk>  as possible suspects, due to their chemical similarity to opiates. Reichelt hypothesized that long term exposure to these opiate peptides may have effects on brain maturation and contribute to social awkwardness and isolation. On this basis, Reichelt and others have proposed a<unk> -free<unk> -free (GFCF) diet for sufferers of autism to minimize the buildup of opiate peptides. Reichelt has also published a number of trials and reviews concluding that this diet is effective.
Gluten-free, casein-free diet
Low-fiber/low-residue diet
Gluten-free diet
Macrobiotic diet
Lectin-free diet
Low-FODMAP diet
Feingold diet
Cotton ball diet