Some people are so obsessed with their food it smacks of zealotry. They might eat only a certain kind of fish cooked on a certain piece of wood. 

They might even believe that they can taste the difference between a strawberry processed at an organic farm and one processed at a conventional one. 

When it becomes truly bizarre, it affects family and friends. Writing at Genetic Literacy Project I discuss people who are on an obsessive quest for health perfection, to an extent that they fetishize their food process.

Now, some people are special and can sense things we cannot. A famous story recounts how Ted Williams preferred one from an identically manufactured set of baseball bats and so the manufacturer weighed it and found it was lighter, just like he said - by a few grams. Guitarist Eric Johnson is so obsessed with tone he even mandates the batteries that go into his effects switch.

Yet without a special bat or certain batteries, neither man would be paralyzed, so that is not a disorder. Ted Williams would still hit .240 in today's game, regardless of the bat he used, and it would only be that low because he would be 96. I could practice every day for 20 more years and not sound like Johnson would sound if he picked up a random Martin Backpacker. 

People who are irrational about food, like anti-GMO activists, don't have an official DSM clinical disorder classification yet, but one may be coming. 

Can psychology explain strident opposition by some to GMOs? by Hank Campbell, Genetic Literacy Project

Citation: Ryan M. Moroze, M.D., Thomas M. Dunn, Ph.D., J. Craig Holland, M.D., Joel Yager, M.D., Philippe Weintraub, M.D., 'Microthinking About Micronutrients: A Case of Transition From Obsessions About Healthy Eating to Near-Fatal “Orthorexia Nervosa” and Proposed Diagnostic Criteria', Psychosomatics DOI: 10.1016/j.psym.2014.03.003