adhslaxer26, I recognize what you're doing, because I've done it myself.

I'd be sneaking food, and would get caught by my husband or kids, and I'd silently be angry with THEM!
I think you have to make a conscious decision to take charge of this "habit". You don't have to do this. It's your choice to eat when when your mother leaves the house, and whatever your relationship with her, it's your hand putting the food in your mouth.
Is there anything you could do when your mom leaves? Something you enjoy that would distract you? Cranking up the stereo and dancing, taking a bubble bath with some trashy magazines...
I know how difficult it is, hon... food seems like our best and kindest friend, but we're just fooling ourselves. Sending you a big hug...