Why do some people feel an urge to eat chalk, ice, or excessive spices?

From chalk and clay to compulsive ice chewing, pica is a recognised condition often linked to iron deficiency and other health issues. A doctor explains why these cravings happen and when to seek help

Many people experience powerful, almost irresistible urges to eat things that are not food, such as chalk, clay, cement, ice or spices, or to consume certain foods in unusually large quantities. Doctors call this condition pica, often linked to iron deficiency and other underlying health issues.

What is pica, and why do these cravings happen?

According to Cleveland Clinic, an American nonprofit academic medical centre based in Cleveland, Ohio, pica is defined as the persistent eating of non-food substances for at least a month, in a way that is not appropriate for someone’s developmental age and not part of cultural practice. This could mean craving chalk, soil, clay, paper, ice, or even consuming unusually large amounts of specific foods or spices like clove.

 

Dr Snigdha Rashmi, Senior Consultant in Internal Medicine at Medanta Hospital, Noida, says pica occurs when normal appetite signals get overridden. “Nutrient deficiencies, sensory preferences, or psychological drivers can hijack the brain’s regulation systems, creating urges that feel deeply physical rather than voluntary,” she explains.

Is pica linked to vitamin or mineral deficiencies?

According to Dr Rashmi, iron deficiency has the strongest and most consistent association with pica, particularly a subtype called pagophagia, which involves compulsive ice chewing. In many patients, the cravings ease or disappear once iron levels are corrected.

 

Zinc deficiency has also been linked to pica, though the evidence is less robust. Calcium, despite popular belief, has very little scientific backing as a primary cause.

 

“Some anthropologists have suggested that geophagy, which is the eating of clay or soil, might once have been adaptive. Certain clays can bind toxins or soothe the gut, especially in environments with contaminated food or water,” says Dr Rashmi.

 

She stresses that clinically, however, doctors take a more cautious view. “While there may be historical or evolutionary explanations, pica today is treated as a pathological condition because of the real risks involved, such as infections and heavy metal exposure, among others,” she says.

Is pica more common in pregnancy, children, and neurodevelopmental conditions?

According to Dr Rashmi, pica is more common during pregnancy, in young children, and among people with autism or intellectual disability.

 

Pregnancy alters nutrient demands and hormonal signals. Children explore the world orally before judgement fully develops. Neurodevelopmental conditions often involve sensory sensitivities and behavioural rigidity. Studies show higher prevalence in these groups, but no single pathway explains every case. 

What are the real health risks of pica?

According to Dr Rashmi, doctors most often see anaemia, heavy metal poisoning (especially from lead), intestinal obstruction, parasitic infections, and dental damage.

 

The danger lies not just in what is consumed, but in how often and for how long. What starts as a craving can turn into an obsession and become a medical problem if left unchecked.

How do doctors test for pica?

“Diagnosis starts with conversation,” says Dr Rashmi. A careful history is essential of what is being eaten, how often, and for how long. From there, doctors rely on a small set of tests, which include haemoglobin and ferritin to assess iron status, and blood lead levels where exposure is possible. Zinc testing may also be included in selected cases.

 

Dr Rashmi stresses pica is not something to laugh at or hide as a behavioural flaw. It is a signal, often pointing to an underlying nutritional or medical issue that can be treated. “When people stop dismissing their cravings as “weird” and start listening to their bodies with curiosity rather than shame, outcomes improve,” she asserts. 

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This content is for informational purposes only and is not a substitute for professional medical advice.