Yeah, quite often. It happens whenever I get addicted to something like a game, or sometimes whenever I'm manic (schizoaffective bipolar is one of my diagnoses).
Lately I've been really into World of Warcraft, been playing with a friend and doing dailies/questing a tonne.
When this happens (mania and/or vidya addiction) I tend to only realise I haven't eaten when my muscles feel incredibly weak and I can't even stand. When it gets to that point, I'll normally order food. It isn't healthy at all.
Right now my food substitute is cigarettes, energy drinks, and sleep - despite having food in my freezer, fridge, and pantry, I just forget to eat.
I wouldn't be surprised if I have a body dysmorphic disorder because whenever I look in the mirror I see a whale staring back at me but apparently I'm a normal weight and have actually been losing weight. I'm too afraid to check the scales.