As fun as this sounds, there's actually an eating disorder which makes the sufferer feel a compulsion to eat non-food items. Pica. It's rare and often occurs with other mental health disorders associated with impaired functioning (e.g., intellectual disability, autism spectrum disorder, schizophrenia).

Common cravings in people with pica include the urge to eat soil, coal, rust, chalk and paper, although people have been known to ingest a much broader spectrum of materials.

Iron-deficiency anemia and malnutrition are the most common causes of pica. In these individuals, pica usually is a sign that the body is trying to correct a significant nutrient deficiency. Treating this deficiency with medication or vitamins often resolves the problems. According to the National Eating Disorders Association (NEDA), the first-line treatment for pica involves testing for mineral or nutrient deficiencies and correcting those. "In many cases, concerning eating behaviors disappear as deficiencies are corrected. If the behaviors aren’t caused by malnutrition or don’t stop after nutritional treatment, a variety of behavioral interventions are available."

"Pica usually appears in people of a low mental age," Gregory O'Brien, professor of developmental psychiatry at Northumberland University, told the Guardian. "So it affects young kids and people with severe learning difficulties." Professor O'Brien said 1%-2% of people with learning disabilities suffer from extreme pica. "It's really not very common but when it occurs, it can be bad."