The formal definition of cachexia is the loss of body mass that cannot be reversed nutritionally: Even if the affected patient eats more calories, lean body mass will be lost, indicating a primary pathology is in place.
Cachexia is seen in patients with cancer, AIDS,[2] chronic obstructive lung disease, multiple sclerosis, congestive heart failure, tuberculosis, familial amyloid polyneuropathy, gadolinium poisoning, mercury poisoning (acrodynia) and hormonal deficiency.