It is easy to understand how our sense of "fight or flight" would have served us well when a herd of wooly Mammoths (the stressor) were about to trample our primitive camp. A sudden shot of adrenaline along with the release of a steroid hormone (cortisol) and we wouldn't have to think about eating until long after the danger dissipated. Ah.. makes you long for the good ole days. Life was simple then as our brain-to-body connection was fine tuned for survival. Now replace the stressor with the fact that you just realized you have multiple places you need to be at the same time and it is easy to see how our physiological response mechanisms can fail us in today's world.

True, there is still a real threat but neither "fight" nor "flight" are viable options. Nowadays stress seldom comes in the form of real physical danger. Although food was probably the last thing on your mind while you were trying to juggle your overcooked schedule of previous commitments, your brain has no idea that you didn't fight or flee. Once the boost of adrenalin is long gone, suddenly your appetite returns with vengeance and eating becomes the activity that your brain associates with further stress release.

To make matters worse, your brain's stress signals have triggered a concern over the fuel that would have been needed when you stood your ground to fight or took off running to seek safer ground. Since your muscles require insulin to utilize sugar in the blood, your brain has inadvertently set the stage for your body to store visceral fat. 

In the long run, it really doesn't matter if your hunger is driven by primitive needs or is merely the result of developing a bad habit. You're going to need a reliable way of breaking the vicious cycle caused by stress. Medical researchers and weight loss specialist both recommend that you exercise more, eat right, get enough sleep, learn to relax, snack on high-fiber foods and avoid alcohol, tobacco and caffeine.