Interesting. I've done a lot of reading/research into trauma and related symptoms...but never run across this one. And come to think of it, I've always found the same to hold true for me, as well...from youth, even, when for example, at school, I'd elect to sit alone at lunch, for my meal. Even when at camp, while on outings, when all would collect in a group to eat...I would take my meal off to a secluded spot to eat, alone.
I wonder if this has something to do with shame, specifically, the inadequacy-related shame arising from "being bested" by one's trauma, as in, the sense of inadequacy of one's resources and reserves as sufficient to measure up against a dangerous world (the terms in which trauma is more and more becoming defined). Maybe it's similar to the reason that women often eat sparingly when on a first date...they fear being judged negatively during this revealingly personal process, as it's difficult to "keep up one's facade of perfection" while doing something which involves such a "dropping of the defenses" in the process, and as such, is so revelatory of our real underlying nature(s). (Of course, I realize that this doesn't apply universally, with regard to ALL women. Just a tendency I've been made aware of by females I've talked to, personally).
On the few occasions I have cooked, I've hated eating my food. I feel really stressed and usually just tear through the food I've made for myself. I actually feel really angry.
But this would suggest that if the above is one of the causes for wanting to eat alone...it's not the ONLY one. In other words, if even when eating alone, you go so far as to actually become angry...then obviously, it's something else, altogether.
I believe it has to do with sensation. When you're eating, your senses are necessarily involved, of course. And in light of "Numbing" being one of the fundamental symptoms of PTSD, this seems to fit.
i.e....if we "Numb" in order to remain "frozen" with regard to sensation...because to feel opens the floodgates to all of the negative stored emotions we're trying to shut out in order to function/remain even-keeled and comfortable...then maybe that includes the senses involved even in eating?
Most I've discussed such numbing with have, as well, attested to the fact that when they do, in fact, begin to experience emotions (sensations), what comes to the surface with them, and overwhelmingly, is anger...even with regard to being in a relationship where the only emotion experienced is loving/being loved by another. I think it may well be because the main emotion we're stifling by this numbing is anger...anger at being traumatized/at the one or many responsible for that trauma.
Maybe the "opening to sensations" implicit even in just eating opens the same floodgates?
That's the only explanation I can think of.