Evidence from clinical trials show that modified fasting (200-500 kcal nutritional intake/day) with periods from 7 to 21 days is effective in the treatment of rheumatic diseases and chronic pain syndromes. Here, fasting is frequently accompanied by increased alertness and mood enhancement. The benefits of fasting are supported by experimental research, which has found fasting to be associated with increased brain availability of serotonin as well as natural opioids (pain relievers) that are produced by the body, known as endogenous opioid peptides, that can have effects similar to those of synthetic opioids. Fasting-induced responses between the nervous system and hormone systems and mild cellular stress response with increased production of neurotrophic factors, which support the development of neurons. These neurotropic factors contribute to the mood enhancement of fasting. Fasting treatments may be useful when used with traditional therapeutic approaches in chronic pain patients. The mood-enhancing and pain-relieving effect of therapeutic fasting should be further evaluated in randomized clinical trials.
DOI: 10.1007/s11916-010-0104-z