What do you call a desire to eat strange objects?

Answer 1

Pica is a medical disorder characterized by an appetite for substances largely non-nutritive (e.g., clay, coal, soil, feces, chalk, paper, soap, mucus, ash, gum etc.) or an abnormal appetite for some things that may be considered foods, such as food ingredients (e.g., flour, raw potato, raw rice, starch, ice cubes, salt). In order for these actions to be considered pica, they must persist for more than one month at an age where eating such objects is considered developmentally inappropriate. The condition's name comes from the Latin word for magpie, a bird which is reputed to eat almost anything. Pica is seen in all ages, particularly in pregnant women, small children, and those with developmental disabilities.

http://en.wikipedia.org/wiki/Pica_(disorder)

http://www.nlm.nih.gov/medlineplus/ency/article/001538.htm