Note: this post addresses cortisol for people who do not have Addison’s or Cushing’s Syndrome.

There are a lot of companies and wellness influencers telling us that elevated cortisol levels pack on pounds around our middles.

But what is cortisol, and do elevated cortisol levels really lead to weight gain? How do we manage our cortisol levels? Why are there so many cortisol lowering supplements?

What is cortisol?

Cortisol is a hormone that’s produced by the adrenal glands, which are little triangle-shaped glands that sit atop our kidneys.

The main role of cortisol is to regulate our stress response. Ever hear of the ‘fight-or-flight’ response? It’s managed by cortisol.

Cortisol release is managed by the HPA (hypothalamic-pituitary-adrenal) axis. When our hypothalamus detects that we’re in trouble, the pituitary gland secretes adrenocorticotropic hormone (ACTH), which tells the adrenals to release cortisol. 

Is adrenal fatigue real? Read my post about it here.

Let’s say you come face to face with a lion in the jungle. This stressful situation causes your adrenals to release cortisol, which causes a cascade of effects in the body, essentially to help you get away from the Lion. Your heart rate goes up. Your digestion slows down, your insulin levels decline, and your liver releases glucose (to give you energy to run away!). 

Cortisol levels in our body change throughout the day. Levels tend to be higher in the morning, which helps us awaken and start our day. In the evening, levels are low, which helps us sleep. Levels slowly start rising again at around 2am.

Aside from the stress response, cortisol also plays a part in metabolism and immune response. It also helps to regulate our circadian rhythm, and helps us form memories. It’s an anti-inflammatory – the same as the corticosteroids you may be prescribed by a doctor for various conditions. That being said, with prolonged stress, elevated cortisol levels may cause widespread inflammation in the body.

We also know that chronically elevated cortisol levels can result in metabolic syndrome, with elevated blood pressure, lipids, and blood sugars.

Can cortisol be a good thing?

Clearly, cortisol is important for a lot of bodily functions, so we don’t want to be afraid of it or eliminate it altogether. We need cortisol. 

Every one of our cells has cortisol receptors, which tells us that cortisol’s effects are felt throughout the body. Transient spikes in cortisol are nothing to worry about. We don’t all have high cortisol, contrary to what some wellness warriors want you to believe. 

Sometimes though, cortisol levels that are too high or too low are beyond our control. 

Addison’s Disease is a condition where the body doesn’t make enough cortisol, so blood cortisol levels are low. The symptoms of Addison’s Disease include low appetite and weight loss, fatigue, muscle weakness, low blood pressure, and dizziness.

Cushing’s disease and Cushing’s syndrome are conditions in which the adrenals secrete much cortisol. Cushing’s causes fat to be stored in the abdomen and muscles, and it’s catabolic – it breaks down muscles and bones. A wide face, purple stretch marks, puffy shoulders and a ‘buffalo hump’ are all signs of Cushing’s.

Cushing’s is fairly rare, and is mainly caused by tumours. Although some people believe that chronic stress may lead to Cushing’s syndrome, there is no evidence to support that. 

cortisol levels and trauma

There is evidence that people who have suffered trauma, especially long-term, have elevated levels of cortisol as a baseline. While cortisol levels should return to normal after the stressor has passed, with long-term trauma, they remain higher.

Stressed people tend to eat more, but this may be more than just behavioural. Weight gain from stress can be multifactorial, including genetics, environment, social determinants, and lifestyle. 

Hormonal reactions to stress – including cortisol secretion – can also make us crave hyperpalatable food, which is thought to in some way ‘soothe’ some of the HPA axis response and make us feel calmer. 

cortisol and belly fat

Cortisol is often described as the ‘belly fat’ hormone. Having elevated cortisol can lead to redistribution of fat into the abdominal region and around the organs. In other words, cortisol mobilizes fat from the cells just under the skin (subcutaneous fat) and puts it in our midsection (visceral fat), likely because the body is trying to protect the organs from the perceived threat.

Unfortunately, visceral fat is associated with more health risks than is subcutaneous fat, so we want to avoid this fat redistribution if at all possible. 

Although research has shown that overweight individuals seem predisposed to higher elevated cortisol levels, results are inconclusive, and not everyone who is overweight or who has belly fat, has elevated cortisol. Even people who are not overweight, can have belly fat due to cortisol levels. 

But remember what I said above: elevated cortisol (outside of Cushing’s) may not CAUSE weight gain. It can cause weight redistribution from subcutaneous fat to visceral fat. It’s also important to mention that some individuals may be more susceptible to this effect. 

Here’s a graphic demonstrating how complex the relationship is between cortisol, stress, and weight:

Some studies show that elevated cortisol levels due to stress can lower our resting energy expenditure after meals, meaning that we don’t burn as many calories. This research about stress and obesity found that for every stressor, subjects appeared to burn 5 calories less after a high-fat meal. It also found that fat metabolism after meals was negatively impacted by stress. 

The study, however, had questionable methodology and the results weren’t remarkable. It was concluded that stressed subjects burned a total of 104 calories per day fewer than non-stressed subjects, however – this number could have been influenced by numerous other things. 

All in all, while we know that the impact of cortisol on metabolism is likely not at a level that’s clinically significant. 

cortisol and exercise

Does exercising too hard raise cortisol? Yup. Be sure to balance high-intensity workouts with lower-intensity ones. You don’t need to go hard every single time you work out. If you’ve been working out for years, especially doing the same sort of exercise, your body does adjust.

Exercise is beneficial to overall health, so don’t avoid it (obviously).

Here’s why you shouldn’t try to burn off your food with exercise.

cortisol and blood sugars

With a perceived threat, the body wants to mobilize as much energy as possible. This helps ensure that we have the means to fight off whatever predator or situation that we’re facing. 

The secretion of cortisol essentially shuts off our insulin, in order to prevent glucose from being stored in the cells. Glucose is also being sent from the liver. These processes cause our blood sugar to rise. Without insulin shuttling glucose to the cells, the cells are still hungry, which can cause us to eat more. 

It can also raise our blood sugars. If you have diabetes, you’ve probably noticed that your blood sugars rise when you’re stressed. 

Our bodies go through all of this stress response, but we’re more likely to be sitting in an office than anticipating a brontosaurus waiting for us around the corner. This may cause us to store the excess glucose as fat.

Stress eating is often about soothing through food, but it can also be about the hunger we feel due to this cascade of reactions.

Having higher body fat naturally increases cortisol levels, but endocrinologist Dr. Karl Nadolsky doesn’t think this is relevant at this point: 

In obesity, the adipocyte 11β-dehydrogenase activity likely promotes higher cortisol compared to inert cortisone, which may lead to adverse metabolic consequences. There is ongoing research into inhibiting this – but not it’s ready for clinical application, to my knowledge.

According to Dr. Spencer Nadolsky, D.O., there is a ‘mild plausibility’ that being stressed has a small effect on abdominal adiposity. 

Still, having persistently elevated cortisol levels isn’t a good thing for our health. It can lead to insulin resistance, high blood pressure, hyperlipidemia, and visceral fat storage – which in itself is a risk factor for disease.

But that doesn’t mean that you should buy into the cortisol-lowering supplements out there.

Cortisol-Lowering supplements

Phosphatidylserine, vitamin C, or rhodiola?? There are a ton of cortisol-lowering supplements out there, but don’t bother. None of these have been proven to help decrease cortisol levels, and many have only been studied in animals. Says Dr. Nadolsky, “some practitioners who prescribe these supplements claim to ‘treat the ‘root cause’ of elevated cortisol, but the stress, anxiety, and sleep apnea that cause elevated cortisol ARE the root cause…and those are causes that supplements often don’t treat.”

Here is a bit of Goop’s Will Cole’s blog post on lowering cortisol:

No, ‘doctor’ Cole, the keto diet is NOT a good way to lower cortisol. What are these people thinking?

Worst idea ever. Restrictive diets cause stress, which can elevate cortisol even more. I see Cole cited the same stress and obesity study as I did above, but he *ahem* interpreted it differently.

Needless to say that anyone who describes a diet as ‘clean, pure, and perfect’ is someone you shouldn’t follow.

Some people recommend fish oils and green tea to lower cortisol, but the research around those for that purpose is sketchy at best. 

One supplement that may help is ashwangandha, which does have a few promising human clinical trials behind it. Prebiotics may also help, but the research is a bit lacking. Still, there’s nothing to lose by showing your gut some love.

cortisol and diet

Even though the internet is full of diet plans that promise to ‘lower cortisol quickly,’ (like the one below) they aren’t valid. Eating anti-inflammatory foods is always a great idea, but the theory that they’re going to lower your cortisol levels is ridiculous.

This article about a ‘one-day plan to balance cortisol levels’ is completely misleading. You don’t ‘balance’ cortisol levels – they’re either high or low – and if you’re chronically stressed, you can’t suddenly decrease your cortisol levels with eggs and greens. You’ll need to stop that stress at the source.

Eating a balanced diet with adequate protein, lots of plants, and as much fibre as possible, is the best prescription for health. Anyone who promises to ‘balance’ cortisol levels is throwing you a red flag.

Do hormone balancing diets work? Read my post on them here.

Your best bet is to lower cortisol levels by implementing lifestyle changes such as better sleep hygiene, not overexercising, saying ‘no’ to non-mandatory events and work projects if possible, meditating, and getting out into nature. 

cortisol and coffee

A lot of cortisol-lowering diets forbid coffee, which I think is a bit of an overreach, unless you’re drinking 10 cups a day.

This study found that women who consumed caffeine before exercise and meals had greater transient cortisol levels. 

Remember that cortisol secretion in the morning helps our alertness. Interestingly, one theory suggests consumption of coffee in the morning, when cortisol levels are at their highest, may interfere with cortisol production, causing our bodies to produce less cortisol and to become more dependent on the coffee for alertness. However, that may depend on a person being caffeine-naive.

If you drink coffee every day, you become tolerant to its caffeine, and cortisol levels reflect that

Should you drink 10 cups of coffee a day? Probably not. But if you’re a regular consumer of a small or moderate amount of caffeine, continuing with that is probably not going to make a difference in your health. 

should you get your cortisol levels checked?

If you feel as though you have issues losing weight, thyroid hormones should be checked. If you have symptoms of Cushing’s or Addison’s, speak to your doctor to have your cortisol levels checked.

cortisol, in short:

  • Cortisol increases visceral fat storage, but the extent to which it causes weight gain is not likely clinically significant.
  • Excess body fat may increase cortisol levels in the body, but not significantly.
  • Elevated cortisol appears to slow metabolic rate, but only by a small amount.
  • Cortisol may increase our desire for ‘comfort food’ during times of stress.
  • We all need cortisol, but prolonged stress and trauma can increase amounts to unhealthy levels
  • Chronically elevated cortisol may increase risk for inflammation, weight gain, high blood pressure, and metabolic syndrome.
  • Elevated cortisol doesn’t mean you can’t lose weight. There is no research to support that theory.
  • There is no diet to lower cortisol. Cortisol lowering supplements are mostly untested or unremarkable in humans, with the exception of ashwangandha.
  • Changing lifestyle to decrease stress, and addressing what’s causing high cortisol directly, may help lower levels.