How Stress Impacts Metabolism & Appetite
How Does Your Mind Influence Your Weight?
Your mind has a tremendous influence over your body’s metabolism and ability to lose weight. For one, your mind’s thoughts are the seeds to conducive behaviors - behaviors such as eating well, exercising, and getting enough sleep which are all important factors. Another less obvious pathway of influence is that your thoughts affect body chemistry. That chemistry controls your metabolism and hunger. When your thoughts evoke stressful feelings, this can change your internal environment in a way that decreases your metabolism and increases hunger.
In this article, we’ll discuss stress, and more specifically the stress-hormone cortisol. You will learn how cortisol can impact metabolism and appetite and what you can do to adjust your mindset in order to reduce the amount of cortisol produced during stressful events.
Stress & Metabolism
Cortisol
The occasional short-term stressor is not the problem; it’s the chronic stress that is. Chronic stress leads to an over-production of cortisol, one of your body’s chief stress hormones. It’s the over production of cortisol that can lead to weight gain or the inability to lose weight. This is true even if you’re eating within your predicted caloric needs. For example, cortisol is a catabolic hormone, and since stress increases cortisol production, your body begins to break down faster than normal. What does this have to do with fat gain? Literature suggests the thyroid, your body’s chief regulator of metabolism, decreases its release of thyroid hormone in response to elevated cortisol. If your thyroid activity decreases, so does your metabolism. In essence, this is your body’s attempt to counteract the catabolic effect of cortisol. When your body turns your thyroid activity down, you’ll gain weight. It seems the body is trying to balance itself out, but unfortunately the down-regulated thyroid activity creates a tilt towards weight gain.
Blood-Sugar Balance
Another reason for stress-induced weight gain has to do with blood sugar stability. When cortisol (a sugar steroid) is elevated, sugar is transferred from the liver and non-working muscles to the blood. This is a normal and important fight or flight response that prepares the body for physical action, but here’s the problem. Most of us are dealing with non-physical emotional stressors, and therefore we end up with high amounts of circulating blood-sugar (glucose). As glucose levels rise, insulin has to be released in order to lower glucose to safe levels. If the emotional stressors are chronic, cortisol and insulin become overly released in an attempt to maintain a healthy glucose level. This blood-sugar rollercoaster makes it difficult to lose or maintain weight. Note: this outcome doesn’t occur in everyone, but if you struggle to lose weight, blood sugar balancing should be considered as part of the solution.
Stress and Appetite
Stress also has another annoying feature. It increases appetite. At least, this is true for about two- thirds of the population. The reason has to do with two of the hormones released when we’re stressed, cortisol and corticotropin releasing hormone (CRH).
When stress first occurs:
CRH is quickly released, and this decreases hunger.
Shortly after, cortisol is released, and this increases hunger.
You would think the two would cancel each other out and normal hunger would prevail, but they do not; and that’s because cortisol stays elevated in the body for much longer than CRH. When a stressor is over, CRH quickly decreases, but cortisol takes 1-2 hours to drop. If you experience stress several times during the day (each stimulating cortisol for 1-2 hours), you can see that your cells are being bathed in excess cortisol for the majority of the day (See graph 1). For all but a third of us, this cortisol will make us very hungry, and the foods we crave during this period tend to be high in carbohydrate and fat. Trying to be ‘good’ and eat the right things will be much more difficult.
Cortisol & CRH During Stress
Graph 1: The onset of a stressor first stimulates CRH (blue line) and then cortisol (red line) shortly after. Cortisol is elevated for much longer than CRH creating an increase in appetite.
Potential Stressors can range from feeling pressured for time, bad news, unhappy with your work or partner, problems with the kids, to deeper unresolved issues such as jealousy and poor self-confidence.
For an in-depth review of the physical and psychological impacts of stress see the book, Why Zebras Don’t Get Ulcers by Robert Sapolsky
Reducing the Intensity of a Stressor
Although the hormonal effects from stress are strong, there is something you can do about it. You can’t always reduce your stressors in life, but you do have the ability to decrease their intensity. By reducing the intensity of a stressor, you reduce how much it depletes you. You also preserve energy levels by using less bodily resources. You reduce stress-hormone output, improve blood-sugar stability, and improve appetite control. You can do this even if the stressor itself hasn’t changed at all; because stress is really just your interpretation (or response) to an event.
Event + Response = Outcome
In the above equation there are three parts; and the one part we always have control over is the response. The hormonal outcome for a stressful event (such as someone cutting you off in traffic) is determined by your response, not the event. An angry response will create a very different hormonal outcome than a slightly annoyed or aloof response. Learning to respond in a more self-supporting way is a skill that anyone can learn, and this leads us to a technique called Attitude Breathing.
Attitude Breathing | From the HeartMath Institute
Attitude Breathing (AB) is a simple technique used to shift your response to an event. Most of the time we respond to stressful events in an automatic manner, as if we’re programmed. Somebody yells and we feel nervous or scared; our tasks are piling up so we feel overwhelmed. These are normal responses, but depleting nonetheless. Here’s how AB works:
Recognize a feeling or attitude that you want to change and identify a replacement attitude. Example: You feel anxious and you want to feel calm. See the table below for more examples.
Focus your attention in the area of the heart. Imagine your breath is flowing in and out of your heart, breathing a little slower and deeper than usual. Suggestion: Inhale 5 seconds, exhale 5 seconds, or whatever rhythm is comfortable.
Breathe the feeling of the new attitude slowly and casually through your heart area.
In order for this technique to work you must have a sincere interest in making the shift. You need to let go of your justification for the negative feeling. Yes, you’re entitled to feel however you want, but harboring negative feelings will only hurt YOU. This is an important point because how often do we hang on to anger, resentment, or frustration just because we’re entitled to? Regardless of entitlement, those feelings will deplete you. They will disrupt your hormones, your blood sugar balance, and a myriad of other problems. The scenario given above about being cut off in traffic is an example of a small stressor. The stressors we face throughout the day can be much larger, with much larger hormonal ramifications.
Although the AB technique is simple, it may be difficult for you in the beginning. Again, you must put forth a sincere attempt to make the shift. As you continue to practice, you’ll slowly improve at naturally responding in a self-supporting manner. Don’t give up after your first few attempts. Stay with it. Learning to respond differently is a skill, and just like all skills it takes practice to hone. If you can’t shift your attitude, then just breathe through it (step 2 above).
Personal Training is Evolving
The world of personal training is evolving. It’s no longer sufficient to assess and teach solely in the areas of physical exercise and general dietary advice. There are many factors to consider when creating a path to better health and fitness. One very important factor is stress; the amount of stress someone experiences will have a direct impact on how well they improve. As personal trainers and wellness professionals, we don’t need to know how to solve everyone’s life problems, but we should at least be aware of the stress our clients are under. This influences exercise prescription, as it’s generally not wise for someone to intensely exercise when they’re under a significant amount of stress. That would only further the problem.
Feel free to leave any comments below. Be well :)
Scott
Scott Bevins is an integrative health & fitness coach who teaches in all domains of health – physical, mental, emotional, and spiritual. He is based in the Turks and Caicos Islands. Schedule an appointment for an in-person or remote consultation.