Nutritional therapy is a complementary medicine that uses nutrition and lifestyle changes to promote an individual's health and well-being. Nutritional therapy is underpinned on the principles of functional medicine (see below). Nutritional Therapists assess and identify potential nutritional imbalances and the underlying root causes of presenting symptoms instead of merely treating the symptoms. They use a variety of tools (which may include functional tests) to develop personalised nutrition and lifestyle programmes to address the symptoms. Nutritional therapists may work independently or collaborate with conventional medicine and other healthcare professionals to provide comprehensive care.