I don't think I have ever met a person who is at a weight which does not satisfy them who has not said, "I eat when I'm stressed." In fact, it's one of those things that people commonly say they have to conquer in order to succeed in their weight loss goals. Well, I have bad news for everyone who has felt that way; it is in your nature, your very biology, to eat when you feel stress.
All animals react to stress by consuming energy if they have access to it. Bees will gorge on honey when stressed. Coral gorges itself when subjected to the bleaching effects it experiences due to global warming. Humans may indulge in a pint of ice cream. Stress causes the body to dive down to glycogen storage in the liver and muscle to get more glucose and to get more glucose from substances in the body other than carbohydrates. The body wants to replenish the stores from these effects. It wants you to eat if you can because the expectation is that experiencing stress means you will soon have to act, and you will need energy to act.
In modern humans, we experience stress related to mental rather than physical threats. In fact, it's no exaggeration to say that we experience worse stress than our ancestors as the years go by. Part of the reason for this is that civilization takes a toll on us. We can't act on our frustration or aggression by murdering a competitor or running away from our problems. We have to sit there and take it for days, months, or years. We have to endure the stress without reacting to it. Our ancestors could escape and return to a less stressful state of being. We cannot.
Since each person responds to stress with a different intensity of reaction (based on their nervous systems and resulting sensitivity), one person may blithely go about their day feeling no suffering. Another, in the same circumstances, may be consumed with anxiety. We cannot choose to be oblivious. We can only choose how we respond, but even then, our biology is directing us to eat.
So, why isn't everyone who experiences stress on a continual basis overweight? Well, more and more people are becoming overweight in developed nations everyday. In addition, the aforementioned differences in sensitivity to stress play a part in whether or not you have a stress response. In order to want to gorge as a result of stress, you have to perceive the stress and we aren't all equal in that regard. Additionally, some people are better at ignoring those cues to eat due to stress or consciously pursue other outlets (such as exercise, sex, or emotional outbursts).
The thing that occurred to me today as I took a long walk for exercise and was gawked at, laughed at, pointed at and treated disrespectfully by far more people than one might imagine was that those of us who are already overweight are stuck in a stress loop. Being fat means you are subjected to stress that thin people are not. You may want to control your eating, but your body is responding to the stresses you feel every time you step out of the house by cuing you to eat. You eat because of that stress and stay fat or get fatter which in turn makes certain that you continue to suffer stress (either externally imposed by judgmental strangers or internally so from your own self-rejection or physical suffering as a consequence of your weight) which again makes it harder not to eat.
I feel anxiety every single time I leave my home, and varying degrees of stress depending on how the winds of fate treat me when it comes to the amount of abuse I suffer and my particular sensitivity on a given day. My life has been a barrage of stress every moment I'm not safely cocooned in my home.
In knowing the biological response to stress, I believe we can gain power. The first point about this from which we can draw strength is in knowing that wanting to eat when you are stressed is not a character flaw. It is nature. The bees aren't beating themselves up for gobbling down honey until they are so bloated they cannot move. You are smarter than a bee, so you can plan a mental response, but you shouldn't berate yourself up for a physiological cue to eat when stressed, nor castigate yourself for resisting and failing anymore than you should be angry at yourself for responding to a grumbling stomach by eating something.
The second way in which this benefits us is that we can control our responses when we can predict them. If you know you are going to endure a stressful situation (like a visit to the doctor or a job interview) and will want to eat, you can plan to eat something after the experience. You can even plan to offer yourself "comfort food" and you can know that there is no need to punish yourself for wanting to comfort yourself with food. If you diet, you can plan a day of maintenance level eating or find some sort of lower calorie "treat" to give yourself what you need. Control does not mean you resist every impulse and bodily cue, but rather that you deal with them in a healthy manner.
For me, this is going to mean some mental work. I'm a very sensitive person. Again, this is not by choice. It is merely my biology. I cannot become less sensitive because I want to anymore than someone with their ear pressed next to a speaker turned up to level 10 can decide to not experience the volume of the sound by will. I've long thought that I should practice meditation to make my overall resting state more relaxed, and I believe this realization about eating and stress makes the need rather more imperative. Though I can't change my nervous system, I can mentally prepare myself to disconnect more effectively from the world around me or at the very least learn to return to a state of mental and physical peace more rapidly through making myself familiar with relaxation techniques. The stress will still be there, but I hope to train myself to "calm down" from it or react differently to it. It may or may not be effective, but it is worth exploring the options.
I think that the link between stress and eating is one that people already understand on a basic level, but they tend not to go beyond the level of blaming themselves for eating in response to stress. In my opinion, lasting weight control needs to adopt an effective plan for dealing with the reality of the biology of stress rather than focusing on simply stopping the fact that we feel compelled to eat under stressful conditions. I have no confidence in "sheer force of will" when it comes to denying the body's basic urges, but I do have faith in our ability to adopt an effective plan to handle them once we become aware of the full scope of the issue.