Stress, cortisol and a body that no longer responds as usual

You sleep, yet you still feel tired. You train, but the results don't come. Your weight is harder to shift than before, and perhaps your body feels swollen, heavy or "inflamed".

It is easy to think: Is it cortisol? My hormones? My thyroid?

Sometimes hormones can play a part. But reality is usually more complex. Stress, sleep, relationships, circadian rhythm, food, training and recovery all affect one another. Cortisol is part of the system – but rarely the whole explanation.

What is cortisol, really?#

Cortisol is produced in the adrenal glands and is a vital hormone. It is not "dangerous". Without cortisol we would not be able to wake up in the morning, deal with infections or regulate blood sugar.

The problem arises when cortisol levels are elevated for a long time. Cortisol's job is to secure access to energy in a potentially threatening situation. To do this, blood sugar rises, energy reserves are mobilised, immune activity changes and rebuilding processes are deprioritised. In the short term this is a fantastic survival mechanism. In the long term it can contribute to poor metabolic health (Beaupere et al., 2021; Gianotti et al., 2021).

Stress, cortisol and insulin: an underestimated link#

One of the most important mechanisms behind stress-related weight gain is the effect on insulin.

Insulin is the body's main storage hormone. When cortisol rises, the liver releases more glucose into the blood. The body responds by releasing more insulin. If this happens repeatedly over a long time, insulin sensitivity can decline, which is usually called insulin resistance (Yaribeygi et al., 2022; Sharma et al., 2022; Beaupere et al., 2021).

Research shows that chronic stress is linked to increased insulin resistance, a higher risk of type 2 diabetes and more fat storage, especially around the stomach and waist (Yaribeygi et al., 2022; Gianotti et al., 2021; Sharma et al., 2022).

That does not mean stress automatically causes diabetes or obesity. But stress can act as an amplifier of other risk factors.

The first step: take a lifestyle inventory#

When people seek help for weight problems, stalled training results or vague tiredness, the focus often lands on calories, training or supplements. But before optimising the details, it is actually much wiser to try to map the whole picture:

• How am I sleeping, and do I have regular sleep times?
• How many hours do I work, and how do I feel at work?
• How do I eat? Do I tend to skip meals during the day and then eat a lot in the evening?
• Does training give me energy – or make me even more tired?
• Do I have time when nobody demands anything of me, or do I constantly feel I am falling behind?
• Do I get enough daylight?
• How are my closest relationships?
• Are there conflicts or other worries that drain energy?

Long-term, chronic stress does not have to feel dramatic. On the contrary, it is common for people to get used to their level of stress and regard it as normal. The body, however, makes no such adjustment. The stress system keeps working even after we have stopped noticing the signals (Yaribeygi et al., 2022; Joseph & Golden, 2017).

What do people mean by "cortisol belly"?#

The term "cortisol belly" is widely used on social media. It usually refers to weight gain around the waist, a bloated stomach or a body that seems to have changed during a stressful period as a result of too much cortisol.

Scientifically, the term is a simplification. There is no recognised medical diagnosis called cortisol belly. There is, however, good evidence that long-term elevated cortisol can contribute to more visceral fat, meaning fat around the internal organs in the abdominal cavity (Gianotti et al., 2021; Beaupere et al., 2021).

When people talk about "cortisol belly", they are therefore often describing a combination of chronic stress, lack of sleep, reduced insulin sensitivity, changed eating habits and reduced recovery rather than an isolated hormonal disorder (Gianotti et al., 2021; Yaribeygi et al., 2022).

Why does it get harder to build muscle?#

Building muscle requires strength training, enough energy and protein, sleep and time for recovery. Chronic stress can disrupt several of these conditions.

Building muscle requires an environment where protein synthesis exceeds protein breakdown.

Cortisol is fundamentally a catabolic hormone. That means it promotes the breakdown of the body's energy stores to release fuel. With long-term exposure, this can counteract muscle growth (Katsuhara et al., 2022; Beaupere et al., 2021).

Studies show that increased cortisol exposure is associated with reduced muscle mass, reduced muscle strength and poorer recovery after training (Katsuhara et al., 2022).

That does not mean stress "takes away muscle" overnight. But if training, sleep and recovery are not balanced, the body may find it harder to build and maintain muscle mass.

Supplements that promise to "lower cortisol"#

The market is full of supplements that claim to "block cortisol", "restore hormonal balance" or work as an "anti-inflammatory detox". The most common ingredients in these supplements are magnesium, phosphatidylserine, the adaptogens ashwagandha and rhodiola (roseroot) and various herbal blends.

Magnesium may be relevant in a confirmed deficiency but is not a general treatment for chronic stress.

Several studies on ashwagandha show small to moderate effects on perceived stress and some biomarkers, but the evidence is not yet strong enough to recommend it as a treatment for stress-related metabolic effects. As for rhodiola, the research is still limited and results vary between studies.

There is no credible scientific evidence that over-the-counter supplements can safely and effectively block cortisol and thereby lead to significant weight loss. The biggest effect still comes from sleep, physical activity, stress management, diet and recovery.

Cortisol: common claims and what holds up#

Dinner settled before a stressful evening#

The lifestyle inventory above asks whether you skip meals during the day and eat a lot in the evening. That pattern is easy to recognise and hard to break when everyday life is full.

Smaklig plans the week's dinners around your goals and your store, makes a shopping list, matches it against ICA's range and puts the cheapest items in your ICA basket, so dinner is settled before a stressful evening. This is what a weekly menu for weight loss can look like. The app does not diagnose anything and does not replace healthcare.

Conclusion: look at the whole load, not just one hormone#

The most important message in this article is also the simplest. If your body no longer works the way you are used to, don't automatically start looking for a hormone that is "out of balance". Look at the whole picture first.

Cortisol is an important part of the stress system, but not a universal explanation for weight gain, abdominal fat, tiredness or stalled training results. "Cortisol belly" and "hormonal imbalance" risk simplifying things that need a broader assessment.

So start by mapping your life instead. Look at your energy and nutrient intake, your training load and your recovery. But don't stop there: also think about your sleep, circadian rhythm and time in daylight, your workload, and your intake of alcohol, nicotine and medicines. It is also worth thinking about your close relationships and how they may affect you, both positively and negatively.

The body does not need a stress-free life. That is neither possible nor desirable. But it does need a reasonable balance between load and recovery. And sometimes the most important change is not another training session, a new diet or a supplement. It is simply discovering what is actually putting a load on you.

When should you see a doctor?#

You should consider a medical assessment if you have:

• marked tiredness that does not improve
• unexplained weight gain
• a sharp drop in training capacity
• menstrual disturbances
• suspected thyroid symptoms
• high blood pressure combined with central obesity
• a suspected hormonal disease such as hypothyroidism or Cushing's syndrome

In these situations, laboratory tests and a medical assessment may be necessary.

About the sources in this article#

Most of the article's factual claims are based on the sources below: reviews and a genetic study indexed in PubMed, plus a review in the journal Endocrines. Smaklig has checked every citation against the source's abstract and, where needed, against the full text. The section on supplements does not yet have source references, and a few wordings have gone back to the author for clarification and will be updated after his reply. Much of the research on cortisol and metabolism concerns greatly elevated levels, for example in Cushing's syndrome or treatment with corticosteroids, and the link with everyday stress is less well established.

Smaklig added the short answer, the table, the section on dinner planning and the frequently asked questions.