New York: Experts can predict with 80 per cent accuracy if someone has anorexia or bulimia by studying five strands.

Boffins at Brigham Young University in Utah say the pattern of carbon and nitrogen molecules in hair changes with diet. Hair is a “chemical diary” of what we eat, and when.

Dr Kent Hatch, who carried out the research, said the test was “objective” and removed a doctor’s reliance on his patient’s “honesty”