I expect the idea vegetarians (who as others have pointed out can have a significantly different diet to a vegan) are more likely to develop ME has been around quite a while. In the late 1980's when I told my GP I was "tired all the time" he asked if I was a vegetarian. He actually said I looked like a vegetarian and when I queried him on that he said it was my long hair. (That's the one and only time I've had a close encounter with an idiot doctor, fortunately! Given the length of time I've been sick I've probably got off lightly.) Is the notion that people who develop ME/CFS are more likely to have been vegetarian, perhaps confused with some evidence people who don't eat meat and who also become iron deficient or possibly B12 deficient could be more likely to develop chronic fatigue?? These people might even return to full health after supplementation? FWIW, Same as someone else mentioned above, my iron levels returned to normal within months of stopping eating grains in 2007. I'm not celiac but there was something else going on there inhibiting absorption. Getting good nutrition seems to be an individual thing?