Cortisol, often dubbed the “stress hormone,” plays a critical role in how our bodies respond to stress. However, when cortisol levels remain elevated for prolonged periods, it can wreak havoc on our health, contributing to weight gain and a host of other issues. For many, elevated cortisol is the primary reason standard weight loss strategies simply do not work.

So, how does cortisol influence weight? High cortisol levels, often caused by chronic stress, can lead to weight gain by increasing appetite, promoting fat storage, and altering metabolism. Managing stress through lifestyle changes and appropriate nutraceutical support is key to maintaining healthy cortisol levels and weight.

Understanding the connection between cortisol and weight gain is just the beginning. To effectively address high cortisol levels, we need to explore its causes, recognize its symptoms, and implement practical strategies for management. In this article, we’ll take a comprehensive look at the role of cortisol in the body, how it impacts weight, and actionable steps to regain control of your health.

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What is High Cortisol?

High cortisol, or hypercortisolemia, refers to elevated (hyper-) levels of the cortisol hormone in the blood (-emia). Cortisol is produced by the adrenal glands, which sit on top of your kidneys. It’s often called the “stress hormone” because it helps your body respond to stress.

The process starts when you experience stress, whether it’s physical (like an injury) or psychological (like a big presentation). Your brain senses this stress and sends signals to the adrenal glands to release cortisol. This system is known as the HPA axis (hypothalamic-pituitary-adrenal axis) – think of it as a communication network between your brain and body. The brain tells the adrenal glands to produce cortisol, which then helps manage the stress by increasing your energy and altering your metabolism.¹ When this system is overactive, such as during chronic stress, cortisol levels stay high, which can lead to various health issues, including weight gain.²

Causes of High Cortisol

There are innumerous ways someone could end up with chronically elevated cortisol levels. However, the same mechanism underlies the vast majority of these situations. This underlying mechanism would be chronic stress and HPA axis dysfunction.

To understand this phenomenon, we must first understand what stress is. As Noushad and colleagues describes, “Stress is a usual psychophysiological response generated by the body due to the undesirable, challenging, and difficult circumstances or stressors.”³ In other words, stress is how the body responds when faced with a difficult situation.

Most stressors are acute, and are an opportunity for our bodies to become stronger. For example, when you lift a heavy weight at the gym, it will be a stress on the body and require special resources to be sent to the muscle. However, a few days later the stress will completely resolve and your muscles will be stronger and more prepared to face the challenge of lifting a heavy weight in the future.

On the other hand, chronic stress occurs when either the stressor or unresolved emotions around the stressor (trauma) persist for long periods of time. Under chronic stress, the body continuously releases stress hormones, mainly cortisol, to try to become stronger, but ends up causing more damage than good to the body.

Interestingly, if stress persists for long enough, the body will go from a chronically high cortisol state to a chronically low cortisol state. ⁴Low cortisol levels have their own set of health concerns and are a topic for another blog post.

Function of Cortisol

Cortisol is a steroid hormone that plays many roles in the human body. As previously stated, it is our main stress hormone, and its main function is to improve resilience under the presence of a stressor. In this way, it is an incredibly important hormone that is essential for survival.

Blood Sugar Regulation⁵

Cortisol plays an important role in regulating blood sugar levels in times of stress. When we are stressed, our body assumes that we need extra energy to get through whatever the stressor is. To do this, cortisol increases the amount of sugar in our bloodstream to provide immediate energy to the brain and muscle cells.

To increase energy supply further, cortisol causes our bodies to break down fat and muscle tissues to be turned into sugar. This enhances the amount of energy available to the entire body.

Inflammation⁶

Cortisol is an anti-inflammatory hormone. It lowers inflammation by suppressing the immune system. This is why steroid drugs that mimic the action of cortisol, like prednisone, are used to lower inflammation in the body.

Symptoms of High Cortisol

People with chronically high cortisol often present with a broad spectrum of symptoms. These may or may not include the following.

Blood Sugar Dysregulation⁷

As previously stated, cortisol increases blood sugar to provide extra fuel in times of stress. However, when stress levels remain chronically elevated, blood sugar levels can remain elevated as well. This leads to high blood sugar (hyperglycemia) and insulin resistance. For this reason, amongst others, chronic stress is often correlated with blood sugar dysregulation, or even overt type 2 diabetes.

Muscle Loss

Elevated cortisol levels cause muscle proteins to be converted to sugar to improve short term energy levels. As one could imagine, chronically elevated cortisol levels would therefore cause muscle tissue to be continuously broken down and lead to overall muscle loss. This phenomenon is well established as a side effect of long term use of steroids (not the same as anabolic steroids)⁸. However, similar effects are also possible from chronic stress.⁹

Weight Gain

The relationship between elevated cortisol and weight gain is well known.¹⁰¹¹ Simply put, high cortisol levels increase appetite while simultaneously redistributing fat stores towards the abdomen and face.¹² Chronic stress in an of itself has been shown to decrease metabolism by up to 100 calories/day.¹³ As a result, those with high cortisol levels will experience weight gain around the abdomen and face. This process is further complicated by the fact that cortisol also decreases skeletal muscle mass. This can in theory lower basal metabolism and lead towards more weight gain.

Cravings¹⁴¹⁵

Elevated cortisol levels have a well known correlation with increased sugar and carbohydrate cravings. For this reason, a strong craving for sweet foods can be a symptom of high cortisol levels in the blood.

Depression

In a high cortisol state, depression often presents as melancholic depression.¹⁶ Melancholic depression is typically defined by a hyper-aroused state, anxiety, low reactivity to environment, weight loss, and undersleeping.¹⁷ Of note, melancholic depression tends to be the worst in the morning.

Frequent Illness¹⁸

Long-term stress keeps cortisol levels high, which throws off the balance of important immune system chemicals, leading to ongoing inflammation and a weaker immune system. This constant high cortisol reduces the number and activity of crucial immune cells, making it harder for the body to fight off infections and illnesses. It can also boost cells that suppress the immune system, increasing the risk of diseases like cancer. So, while short-term stress can help the immune system, long-term stress weakens it, making the body more vulnerable to health problems.

Diagnosis of High Cortisol

Diagnosis of elevated cortisol is a two step process that may include blood or salivary testing.

Cushing’s Syndrome

The first step in investigating cortisol levels is to rule out overt diseases of cortisol dysregulation. In the case of cortisol excess, Cushing’s Syndrome is a condition that must be investigated first. Cushing’s Syndrome is a disease where the body produces too much cortisol. This is usually caused by a tumor on the pituitary gland or adrenal glands.

Signs and symptoms of Cushing’s Syndrome include:¹⁹

weight gain
thin arms and legs
a round face
increased fat around the base of the neck
a fatty hump between the shoulders
easy bruising
wide purple stretch marks, mainly on the abdomen, breasts, hips, and under the arms
weak muscles

Various tests may be performed to make a diagnosis of Cushing’s Syndrome. If you have these symptoms, please be advised by your medical team.

Adrenal Dysfunction

Adrenal dysfunction is a term used to describe a set of non-specific symptoms that are thought to arise from the over- or under-secretion of adrenal hormones. While allopathic practitioners tend to only recognize overt diseases of the adrenal glands, such as Addison’s disease, Cushing’s disease, or adrenal tumors, functional practitioners recognize abnormal variations in adrenal hormones (cortisol, DHEA, pregnenolone, etc.) as significant and worthy of appropriate intervention.

In regards to elevated cortisol levels, adrenal dysfunction would be “diagnosed” using a multi-point salivary cortisol test. This test collects saliva samples at multiple points throughout the day to see if cortisol levels are following an appropriate circadian rhythm throughout the day. If cortisol levels are elevated at multiple points, a functional practitioner will make the “diagnosis” of adrenal dysfunction.

Treatment of High Cortisol

For the purposes of this blog, I am specifically speaking about high cortisol levels within the realm of adrenal dysfunction, not Cushing’s Syndrome.

Diet

Timing: For reasons not entirely understood, cortisol levels will rise following a meal. When a meal is skipped, the following meal will result in a compensatory cortisol spike that is much larger than normal. This is likely a combination of a normal postprandial cortisol spike stacked atop increased HPA axis function intended to stimulate hunger and possibly kickstart gluconeogenesis (the production of glucose from protein and fat).²⁰ For this reason, maintaining blood sugar balance and having consistent meal times is often recommended for balancing cortisol levels.

Carbohydrates: Some evidence suggests that a low carbohydrate diet can be effective in treating the metabolic consequences of a high cortisol picture.²¹ This appears to be especially true for the peripheral metabolic consequences of HPA axis hyperactivity (obesity, RAAS activation, cortisol metabolism, etc.).²² However, it has also been demonstrated that nutritional ketosis does increase HPA axis activity and can result in an increase of cortisol secretion. Some research suggests that resting cortisol levels will normalize after 3 weeks on a low carbohydrate diet in men.²³ This is thought to be from the amount of time needed to maintain steady ketone supply to the brain.

Protein: High protein diets have been associated with increases in cortisol levels. Protein greater than 35% total energy intake can exceed the liver’s capacity to deaminate proteins through the urea cycle.²⁴ Thus, ammonia can build up and cause a variety of toxic effects. As an attempt to increase deamination capacity, the body may increase cortisol secretion and lower testosterone levels.²⁵ These hormones increase and decrease urea cycle activity respectively.

Fermented Foods: Lactobacillus casei strain Shirota was found to decrease cortisol related symptoms following a psychological stressor. This strain likely prevents hypersecretion of cortisol following stress and may be a potent strain of psychobiotic to use for adrenal dysfunction.²⁶ Another lactobacillus based probiotic, L plantarum P8 has shown clinical efficacy in reducing anxiety when administered over a 12 week period.²⁷ Generally speaking, promoting the integrity and health of the gut through pre-, pro-, and postbiotics will have a wide-reaching benefit to many aspects of adrenal dysfunction as shown in the diagram below.²⁸

Exercise

Magnitude: Though intensive exercise is capable of increasing cortisol levels, the magnitude and onset of cortisol secretion is much smaller in relation to psychological stress.²⁹ Moderate intensity exercise in which blood glucose remains stable will typically not increase cortisol levels.³⁰ Intense exercise during the day has been shown to cause decreased cortisol levels throughout the night.³¹

Fuel: Exercising while on a low carb diet appears to cause a significant spike in post-workout cortisol levels as compared to high carb diets.³² Providing carbohydrates during exercise can attenuate post-workout cortisol elevations in general. This would be a supplement of 1 liter of 6% carbohydrates per hour of exercise.³³ Supplementation of amino acids (arginine, valine, and serine) has also been found to assist in blunting the post-workout cortisol spike as well.³⁴ Additionally, it is of utmost importance to hydrate adequately. Dehydration can cause increased thermal stress and relatively increase cortisol levels through a decrease in blood volume.³⁵

Nutraceuticals

Vitamin C:³⁶ Clinical studies show vitamin C to be particularly effective in lowering cortisol secretion in response to a perceived stressor through modulating the HPA axis. Data also shows that vitamin C is also able to lower perceived stress without modulating cortisol levels. This supports the hypothesis that vitamin C is able to lower stress levels through both adrenal and extra-adrenal pathways. These studies used up to 1,000 mg sustained-release ascorbic acid three times daily.

Magnesium:³⁷ Chronic stress has been shown to lower total levels of magnesium in the body. This is because stressors, both acute and chronic, lead to increased clearance of magnesium through the urine. Over time, total magnesium levels drop and cause further susceptibility towards stress and depression. Herein lies the vicious cycle of magnesium depletion on stress levels. Supplementing 250 mg/day has been shown to both replete erythrocyte magnesium and lower serum cortisol levels. Doses of 400 mg/day are shown to increase heart rate variability, a proxy of parasympathetic tone.

Ashwagandha: Doses as low as 240 mg (35% withanoside glycoside) were able to lower morning cortisol levels and anxiety scores by 41% on average over the course of 60 days.³⁸ Additionally, this dose was able to raise testosterone levels in men, but not in women. One study found 300 mg of a full spectrum extract for 60 days to lower stress scores by 64.2% and anxiety by 75.6%.³⁹ It was also found to lower cortisol levels by 27.9%. Another study found that 300 mg of sustained release ashwagandha for 90 days gave an 83.4% greater probability of achieving control over stress.⁴⁰

Conclusion

In conclusion, understanding the role of cortisol in our bodies is essential for managing stress and maintaining a healthy weight. Chronic stress and elevated cortisol levels can disrupt many bodily functions, leading to weight gain and other health issues. By recognizing the signs of high cortisol and addressing its root causes, we can take effective steps to manage stress through lifestyle changes and nutraceutical support. This holistic approach not only helps in balancing cortisol levels but also promotes overall well-being, allowing you to regain control of your health.

*** Please consult with a healthcare professional before making any significant changes to your diet, exercise, or supplement regimen, especially if you have underlying health conditions.

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Justin Perr, MS, RD, IFMCP

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Justin Perr is a Registered Dietitian and Certified Functional Medicine Practitioner specializing in weight loss and gut health. He helps patients uncover root causes and achieve lasting results with science-backed nutrition.

High Cortisol: A Functional Guide

What is High Cortisol?

Causes of High Cortisol