The 21st century is an environment of ever-increasing complexity. With that comes a multitude of new ways how we can become stressed, and being constantly stressed is not something you would want. If you don’t know why, then read further.
Let’s talk about stress first. Stress and its perception are highly dependent on the person and his personality. Two completely different people, who differ in how neurotic they are, will react completely different to the same environmental stressors.
- Part I. Stress
- Part II. The consequences
- Part III. The (neuro)biology of stress and rewards
- Part IV. The scary part
- Part V. Help?
It can be “good” or “bad”. It’s commonly divided as such, but the division itself is rather artificial. Stress is commonly a highly challenging, uncontrollable and overwhelming emotional or physiological stimuli (or series of stimuli) which activate an adaptive or maladaptive response that is initiated to regain homeostasis in your body.
It is considered “good” when you think of it as a challenge and are not impaired by its presence. Moreover, it can enhance your performance at some tasks. It is considered “bad” when you are not able to cope with it in a productive way which then hinders your daily activities.
Common emotional stressors include conflicts with other people, breakups, unemployment, exams, and similar things. These events are usually perceived as bigger stressors. There are, however, daily stressors which are generally smaller in perceived size. There are also some common physiological stressors which every one of us experiences quite often. These include hunger, insomnia or sleep deprivation, extreme illness, hypothermia, withdrawal states from drugs, etc.
Besides the source of stress, emotional or physiological, stressors differ in their duration as well. Short-term (acute) and long-term (chronic) stressors affect the body differently. I will explain more about this in the second part. High levels of prolonged and possibly overwhelming stress disrupt your body’s homeostasis – your body’s ability to maintain optimal internal conditions. Because of prolonged periods of stress, your body tries to adapt again to meet physiological stability, and to maintain stability when confronted with the new stimuli. However, its ability to do so is somewhat diminished.
The amount of stress and its perceived size on your life are both critical risk factors for the development of addictive disorders, as well as the relapse to addictive behavior. Hence, jeopardizing the course and recovery from these illnesses. As we can see below, people who drink the most alcohol are also the ones who feel stressed the most.
But there is more. There is a significant and positive association between highly stressful events, chronic stress and weight gain [1, 2, 3, 4]. This means that people who live in an environment that is more stressful also tend to be more overweight, as you can see in the next picture.
I’ve mentioned that stress differs in length. On that note, I should also mention that chronic stress is the one we should be more worried about. Continuous, chronic stress is the main risk factor which increases our vulnerability to addiction. You’re more likely to relapse or start a new addiction during times of intense perceived stress . Maybe unsurprisingly, but, multiple studies have found this relationship to be very strong in overweight people and those who binge eat [2, 3, 6], but not in lean people. This suggests that there is another factor behind all of this.
I’ve mentioned how food addiction and night eating syndrome work in my previous articles. While the symptoms of the latter hold true only for a certain percentage of people, there is a multitude of behaviors which are shared in food addiction, night eating syndrome, and chronic stress. I’ve even mentioned how chronic stress is the main trigger of night eating syndrome disorder in people.
Not only are higher amounts of stress related to being overweight, people tend to drink more alcohol, and smoke more cigarettes. This was found when they excluded the possibility of age, race, gender, or the socioeconomic status of people to play a part in this equation. 
One way how chronic stress affects us negatively is by creating a state of metabolic dysfunction. It disrupts our body’s normal metabolic and hormonal state. This includes the normal functioning of glucose and insulin. This is partly because your body tries to regain homeostasis and enable everything to work normally again.
However, chronic stress isn’t the only kind of stress that affects us in a negative way. Certain studies show that short-term stress significantly alters eating as well. Some people eat more while others eat less, it seems to affect people differently. On average, lean people tend not to eat during periods of short-term stress, while overweight people tend to eat more. They tend to find more comfort in food when under stress. And what is most interesting, we tend to pick extremely tasty, calorically dense foods when under stress. This includes food that is full of fat and sugar [2, 3, 9, 10, 11, 13, 14, 15]. The biological basis of this will be explained shortly.
Four out of ten students report that they eat more food in general when they’re under stress.
Three in four people report that they snack more when they’re under stress.
I suggest brewing a pot of coffee, you’re in a for a read now. You also might want to skip it if you have no background in biology.
Let’s talk biology. There’s two interacting ways how a response to stress is manifested. The first is the HPA (hypothalamic-pituitary-adrenal) axis and the second is the autonomic nervous system (ANS). Both ways influence inflammatory cytokines and immunity, however, the HPA axis is the one to stimulate cortisol to be produced.
Cortisol is a glucocorticoid which is released as a response to stress and low levels of glucocorticoids. Its main roles are increasing blood sugar through gluconeogenesis, suppression of the immune system, and a helpful role in the metabolism of fat, protein, and carbs.
Cytokines are small proteins important in cell signaling. They modulate the balance of the immune response of antibodies and cells.
These hormonal changes occur in order for the body to return to a state of homeostasis. A body’s short-term response to stress is actually supposed to decrease our desire for food [9, 17]. It invokes a short-term response which includes your blood being diverted from your digestive system to your muscles and your brain, in a classic flight or fight response. Your body is prepared either to fight or run away from imminent danger. In such circumstances there’s no time for food, so the desire for food, and the organs required to digest it, are “turned off”.
The chain of events which happen as a response to stress is rather long to explain, I’ll stick to certain changes important for hormone disruption. Your hypothalamus which gets affected by the release of cortisol is very important for leptin, an appetite inhibitor, and ghrelin, an appetite promoting hormone . And here’s the thing. Glucocorticoids (cortisol) increase leptin and ghrelin levels, ghrelin itself gets further increased through stress, and is then continuously increased when subject to chronic stress. This probably increases the amount of food eaten when we are experiencing chronic stress.
And now let’s explore chronic stress a little more. It basically disrupts the processes I’ve described before. Your HPA axis gets dysregulated – this affects all the future events in this chain. Chronic activation of the HPA axis also alters the metabolism of glucose, promotes insulin resistance (not a good thing), and through chronic increases of cortisol it promotes belly fat storage as well. This chronic increase in glucose and insulin levels, as well as the increased preference for calorically rich foods together, have devastating effects on your health.
The reasons why we love fatty, sugary, and calorically rich foods are based in evolution and our brain’s chemistry. There is another pathway which gets activated and is connected to your brain’s please centers. This pathway is called the mesolimbic pathway (also called the reward pathway, but this idea is still being discussed), and it partly regulates the hypothalamic stress circuit. Stress and cortisol are believed to have an impact on reward seeking behavior. [2, 4, 17]
Highly tasty food and high levels of chronic stress together very probably alter your eating behavior and affect the reward/motivation pathway in your brain. In return, you want and look for more tasty food. These behaviors induce your weight gain and functionally change your metabolic, neuroendocrine, and neural pathways. And these in return increase your food cravings and food intake.
Moreover, exposure to long-term stress affects parts of your brain which increase your impulsivity. This means that it’s more likely you will eat something when confronted with different available foods, completely based on your impulses. [18, 19]
Highly tasty food is rewarding as it stimulates the brain reward mechanisms which, in turn, increase the likelihood that you will want to eat these foods again. This is the basic premise of all junk food, the majority of processed food, and so on. You eat it because it makes you feel good more than other foods do. You’re predisposed to seek food that’s highly rewarding to you, we are not rational beings when it comes to food, and we rarely make rational judgments about food for prolonged periods of time (!), especially when we’re presented with highly “brain rewarding” food.
You become conditioned to eating this kind of food, you become more motivated, and you crave it more. There are also real changes in the metabolism of carbs, fat, insulin sensitivity, as well as appetite hormones (ghrelin, leptin) which influence the reward regions involved. All of these change in the direction of you wanting more food. [20, 21, 22, 23, 24]
So these changes, which happen as a result of chronic stress, affect your normal hormone production. They also functionally change your ideal brain chemistry as well. All of this is accompanied by the presence of an ever-increasing stressful environment of the 21st century.
Sadly the answer is not simple.
As far as stress goes, two studies with people who have type two diabetes incorporated stress management in their weight management program. They observed that it was effective in improving stress, food cravings, as well as certain physiological functioning which was being affected by exposure to stress. [25, 26]
With that in mind, I’ve written a piece on emotional awareness and mindful eating.
Both of these easily applicable tips can be useful for reducing stress levels and being aware of your surroundings. Exercise is another great way to cut chronic stress, weight training itself has so many many health benefits that everybody should be doing it.
For a lot of people, reducing stress levels will be extremely helpful in the long run to maintain a healthy lifestyle. Finding a way which helps you personally is the most important part. Different things work for different people.
Chronic (long-term) stress will, through a disruption of your ideal hormonal and brain functioning, very probably make you fat. It will increase your desire for fatty, sugary, and otherwise calorically dense food. This will be continued in a neverending spiral until you remove long-term stressors from your environment or learn how to reduce/cope with them.