Since the publication of the first GAPS book, Gut and Psychology Syndrome, in 2004, the GAPS concept has become a global phenomenon. People all over the world have been using the GAPS Nutritional Protocol for healing from physical and mental illnesses.

The first GAPS book focused on learning disabilities and mental illness. This new book, Gut and Physiology Syndrome, focuses on the rest of the human body and completes the GAPS concept. Allergies, autoimmune illness, digestive problems, neurological and endocrine problems, asthma, eczema, chronic fatigue syndrome and fibromyalgia, psoriasis and chronic cystitis, arthritis and many other chronic degenerative illnesses are covered. Dr. Campbell-McBride believes that the link between physical and mental health, the food and drink that we take, and the condition of our digestive system is absolute. The clinical experience of many holistic doctors supports this position.