Nutritional Therapy is based around the functional medicine model. Functional medicine is a model that is quite different to the conventional medicine model that we are all familiar with.
Conventional medicine primarily aims to make a diagnosis based on an individuals symptoms and treat those symptoms with appropriate pharmaceuticals/treatment. Functional medicine, on the other hand, aims to find the root cause of the symptoms, treating symptoms as indicators of underlying imbalances within the major body systems (digestive system, immune system etc). It is believed by functional medicine practitioners that the body systems are interconnected and that an imbalance in one of these systems may lead to imbalances in others.
Understanding an individuals genetics, history, and how each system is functioning gives insight into the potential root cause of the symptoms a person may be experiencing.
For more information about functional medicine please visit; https://www.ifm.org/about/