Since nutrition is our area of focus here at Reframe Wellness, we’re often asked about the impact of stress on appetite. Or maybe more accurately, we’re often given stress as an excuse for why it’s so difficult to stick to healthier food choices. And you know what we say? We say this is a completely valid excuse. It’s more valid than the people using it even understand.
Stress is our body’s reaction to a perceived threat. This can include threats to our physical, mental, or even spiritual well-being. According to Brian Seaward, PhD, in his book Managing stress: Principles and strategies for health and well-being, Eastern cultures consider stress to be the absence of inner peace, while Western cultures consider it to be any degree of loss over emotional control. Regardless of the perspective we take on it, it is pretty hard to argue that it doesn’t impact every area of our lives, including our physical health.
As we can see in both the Eastern and Western concepts, stress is generally thought of as a feeling or emotion. It sure is that, but it’s also so much more. The feeling corresponds with a physiological response in our bodies, and that has real, physical outcomes.
The feeling of stress is invariably accompanied by production of hormones, one of which is cortisol.
You’ve probably heard of cortisol referred to as the stress hormone, for very obvious reasons. Cortisol is not the only hormone produced during a stressful situation, but it is the one directly responsible for our inability to stick to our healthy eating goals. Let’s talk about it.
Throughout history, our ancestors’ greatest sources of stress were things that threatened their lives. For example, a bear, snake, natural disaster, or an angry stranger with a spear. When faced with any of these things, it’s useful to be able to do something other than stand there and get killed. Thankfully, our bodies are smart. When faced with danger, our bodies produce the hormone cortisol, to give us a burst of immediate energy to facilitate fighting or fleeing (or whatever else might help keep us alive).
Both of these natural instincts (fighting and fleeing) require a LOT of immediately available energy. The most abundant source of stored energy in our body is glucose, which is why the main purpose of cortisol is to encourage our body to access the glucose that we’ve stored away for just this situation.
When this process works properly, a stressful encounter will quickly result in production of cortisol, which in turn stimulates production of a hormone called glucagon, which releases stored glucose into the blood stream to then be used as quick energy for vigorous activity like outrunning an avalanche.
Our bodies store glucose (energy) in the form of glycogen in our liver and triglycerides in our fat cells. Glucagon is the only hormone capable of breaking down stored energy or nutrients in our bodies. If we need to access energy, we must produce glucagon, which then facilitates the stored energy’s escape from the storage cells into the bloodstream where it can then be useful. As previously mentioned, when this is working, it’s an amazing process. Unfortunately, this cortisol to glucagon to big burst of energy process doesn’t happen in all of us.
There’s another hormone that’s kind of a big deal in our bodies, and while it’s not part of this stress process, it can and does interfere with the process in many of us.
That hormone is insulin. Glucagon, which is the hormone we need to produce for a healthy stress response, just so happens to be inextricably linked to insulin. They’re both produced by the same organ, the pancreas, and they facilitate opposite processes in our body. Insulin facilitates the use of energy by cells, then once we’ve used all we can, it facilitates the storage of energy for use later (and why it is often referred to as the ‘storage hormone’).
Insulin stores energy, glucagon releases stored energy. For these reasons, we can only produce insulin or glucagon at any one time. Not both. This inconvenient fact throws a big wrench into the healthy stress response for a lot of us.
Let’s imagine that we are a modern human, and we encounter, not a hostile stranger with a spear, but a hostile boss with a dismissive attitude. Our body responds just the same now to a stressor as our ancestors’ did, despite the boss scenario not requiring a physical fight or flee reaction. We feel stressed, our body produces cortisol, which attempts to raise our blood sugar (aka provide immediate energy) by promoting glucagon. For many of us modern folks, this is where the process breaks down.
If our body is already producing insulin because we ate recently (or because we have insulin resistance and tend to continue producing insulin long after we actually need it) then no amount of cortisol will be able to stimulate glucagon. Remember, we cannot produce insulin and glucagon. The pancreas can only produce one or the other. And here’s another not awesome fact: Insulin is the most powerful hormone in the body. Glucagon can never interrupt or take precedent over insulin.
Stress produces cortisol, which tells our body that we need energy immediately, but we can’t access any stored energy if we’re currently producing insulin, which only uses or stores currently available energy. So what happens then?
Well, there is another way to get access to quick energy. Eat!
Now you can see why in this modern world where so many of us are already struggling with insulin resistance, stress causes hunger and cravings. Stress eating is not, nor has it ever been, a psychological weakness. It is not a matter of willpower. It is not a moral failing. It is the physical response of your body to stress, the perceived need for immediate energy, but the inability to access internal energy stores.
This is how stress makes so many of us eat more and gain weight, continuing the cycle of insulin resistance and ill health.
When the body is not already busy producing insulin, then this stress to cortisol, to glucagon, to energy process does what it is meant to do. That’s why we all know a few folks who always seem to lose weight during their most stressful experiences. If the body is able to access the energy it already has, then there is no need to stimulate hunger. Their body has prepared lots of energy for them to use, but our modern stresses don’t require the enormous amounts of energy that our ancestors needed. Calmly explaining to your boss why he or she should in fact consider your point of view requires significantly less energy than wrestling a bear, but our bodies try to provide us with the same amount in both circumstances. In those who manage to access that energy without eating, they need to do something with it, which results in them not feeling hungry and perhaps pacing or fidgeting like crazy. Again, this is a physiological response, not a mental disorder.
In the presence of insulin, this stress to cortisol, to glucagon, to energy process stops at cortisol. There is no glucagon. There is no stored energy release. There is only hunger and cravings, because our body believe that it needs more energy than it has access to. Then, there is inevitable weight gain, because when we eat, we produce more insulin, which keeps the cycle repeating. Whatever energy we do not use in that stressful moment, insulin will store in our fat cells for later.
But wait, there’s more!
If you thought that stress and cortisol only influence appetite, you’re sadly mistaken. Cortisol does something else that can have devastating effects on our health: It suppresses our immune system.
In addition to accessing immediate energy, cortisol also slows or stops processes in our body that aren’t involved in fighting or fleeing, so that we can focus all the available energy on the task of staying alive. Evolutionarily, this is smart because there’s really no point in healing if you’re dead. So, our bodies use this energy to stay alive. They’ll worry about fixing you up later, after the danger is passed.
When we are stressed, energy is diverted from immune processes. That means everything already going wrong in our body will get worse. Literally everything. If we have a chronic condition, the damage is still being done, but we aren’t able to heal it as quickly when we’re stressed. This is how stress induces flare ups of autoimmune conditions or worsens cancer outcomes. The stress itself doesn’t cause any harm to our body, it’s an important and even useful process, but when it happens every day, we can’t heal. It’s no wonder stress is correlated with worse health in general, and worse health outcomes in specific diseases.
We know the only goal of stress, and its accompanying hormone cortisol, is to provide immediate, focused energy to our body so that we can perform some great feat of fighting or fleeing in the face of danger. This doesn’t translate well into modern times when our stressors are much less deadly and tend to last much longer, but we can’t undo millions of years-worth of biology, so here we are.
Stress is not just a minor inconvenience or a badge of honor to get sympathy with, it has biological repercussions.
It can worsen insulin resistance by inducing hunger, and it can worsen every chronic condition and systemic inflammation by suppressing our body’s ability to heal. We should all take stress more seriously.
What can we do about it? Well, if reducing chronic stress and cortisol’s impact on our health is the goal, all we need to do is find ways to escape the stress. You may be saying, “Yeah, but it’s not that easy.” But it is. In fact, we are so good at doing this thing, we even forget how easy it is. What is this thing that is so easy, you ask? Distraction. Yep. See! You know you’re good at this already. The simplest way to escape stress is by distracting ourselves, but specifically through distractions that let our minds slow down, and then slow the production of the stress hormone. This doesn’t have to be anything expensive, time consuming, or existential at all. A simple walk in nature, rediscovering a hobby like knitting, watching a funny show, or calling a friend who makes you smile, these are all great. It doesn’t have to be complicated, it just needs to pull your mind out of focusing on the stress. It’s okay to focus on yourself sometimes, even if it feels frivolous.
Your health may just depend on it.
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