I have heard of it. For me, when I was sick, that's how my eating disorder started. First I cut out red meat, then I started to exercise more and eat "clean" foods. Then I started restricting more and more. And then it became a real problem. It's hard for me to balance now between eating healthy and am I getting sick again. It's a bit triggering sometimes.

As far as I know it's not technically classified as an eating disorder in terms of the DSM or ICD codes, but it can lead to trouble if someone starts with maladaptive behaviors such as restricting, purging, or over-excerising.