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How does a keto diet affect stress hormones?

Last updated: Feb 9, 2020 at 3:38PM | - Published on: Feb 14, 2019

Written by Sarah Neidler, PhD

Scientifically Reviewed by Raphael Sirtoli 

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Stress hormones and their role in the body

As the name suggests, stress hormones are released in response to stressors – things that demand of your body a timely and adaptive response. Hormonal responses to stress are useful but they are also unhealthy when they occur too often or the stressors aren’t ones you can adapt to beneficially. Liver damage from alcohol is evidence that alcohol is not a healthy stressor, obviously, but getting a little tan under the sun is a healthy response to a stressor (sunlight).

Stress is usually accompanied by increased energy demand. Therefore, an acute stress situation results in an immediate glucose release into the bloodstream, which provides energy for the so-called fight or flight response. The main players in response to stress are adrenocorticotropic hormone (ACTH), glucocorticoids such as cortisol, adrenaline (also known as epinephrine) and noradrenaline (norepinephrine).

  1. Stress first triggers the release of corticotropin-releasing hormone (CRH) in the hypothalamus, a deep-seated part of your brain.
  2. This, in turn, stimulates the pituitary gland to release ACTH.
  3. ACTH goes into circulation to stimulate the production of glucocorticoids in the adrenal glands.
  4. Finally, glucocorticoids trigger the production of adrenaline and noradrenaline and release into the bloodstream from the adrenal glands (the glands sitting above your kidneys)

Adrenaline and noradrenaline are involved in the execution of the fight or flight response. As a result, blood glucose levels rise, as well as heart rate and blood pressure [1]. This system is regulated and fine-tuned by feedback loops so that the reaction to stress is limited and only temporary.

So what triggers a stress response? This can be all kinds of stress factors, such as illness, sleep deprivation, exercise and a drop in blood glucose levels.

So in short, stress leads to an increase in blood glucose, heart rate and blood pressure. A rise in blood glucose will stimulate insulin release, but stress hormones such as adrenaline and noradrenaline will also inhibit its release [2]. Why is that? To reduce the uptake of glucose by muscle cells and make it available for the brain. By this mechanism, the brain has enough energy to make important decisions in a stressful situation.

How ketosis affects stress hormones

When it comes to stress hormones, the ketogenic diet has the reputation of being ‘a stressor’. It is often said to put the body in “starvation mode” and to increase the levels of stress hormones. This would mean that ketosis is inherently stressful compared to higher carb diets.

Is this true? Do we have a sweet potato emergency on our hands?

No. When you start a ketogenic diet after decades on a high-carb diet, it is, of course, stressful for your body to deal with symptoms of carbohydrate withdrawal. You deprive your body of its well-known source of energy (glucose) and force it to use fat and ketones instead. After such a long time on a high-carb diet and food availability around the clock, your body has forgotten how to use fat as fuel efficiency. This is, of course, stressful for the body and causes the well-known keto-flu.

For more information, check out our post about the keto-flu and how to cure it.

During this initial phase, a ketogenic diet increases stress hormones, such as adrenaline, noradrenaline, and cortisol [2].

infographic showing the relation between a keto diet and cortisol levels

This is, however, a healthy (physiological) and not an unhealthy (pathological) response. First, it is happening in a low insulin context. Now that you’re more reliant on fat and insulin is low, all that’s needed is your nervous system to rev up the process of getting fat out of your fat cells (lipolysis). How? With stress hormones! The stress hormones are liberating fat to burn fat in a low insulin context.

Liberate enough fat and you get ketones. Ketones are a great source of energy, and as soon as you are keto-adapted, your body loves this new source of energy. It also soon becomes another option for your brain to use as fuel, which it happily will.

How long does it take to become keto-adapted and for stress hormones to be back to normal levels? Do they go ‘back to normal’? That seems to be very individual. However, multiple studies showing that after a few weeks on a ketogenic diet, the levels of stress hormones are not higher than baseline [3,4].

Beware! A ketogenic diet initially leads to a loss of salt and other electrolytes. Because electrolytes are essential for the body, this can be a very noticeable stress factor and cause an additional stress response – and not a positive one. You can easily avoid it through proper supplementation [5].

The effect of calorie restriction on stress hormones and blood glucose?

The situation is a bit different when following a calorie-restricted ketogenic diet. The ketogenic diet is known for its fat-loss benefits. Many people thus adopt it to lose fat, and to lose fat, they usually believe severe chronic caloric restriction is the most important thing. The myth that counting calories works, persists. Consequently, many people complain of having low energy and being stressed due to keto, when in fact they’re simply not eating enough. It’s unbelievably common amongst women, as they’re targeted particularly strongly with the message that fat loss is all about will power and deprivation.

Fasting involves physiological adaptations that are also stressful triggers. For one, there’s a drop in blood glucose, at least temporarily. In response to the low glucose levels, growth hormones, adrenaline, glucagon, and cortisol are released, which all together help to increase blood glucose.

infographic showing the relation between stress hormones and blood sugar levels on a keto diet

Ketogenic diets tend to naturally result in unconscious caloric restriction, a large reason behind its immense success amongst the obese. Maybe it’s because it normalizes appetite, increases daily energy expenditure or resolves gut-mediated inflammation – who knows! What matters here, is that unconsciously restricting your calories is not stressful, but consciously restricting them is. So don’t worry about keto being inherently stressful, it’s not, humans are evolved to be in this state day to day.

Assuming that you have sufficient fat stores,  as we nearly all do, your body can happily burn stored body fat and rely less on an external energy supply (food). This is one reason, why the ketogenic diet allows you to lose weight without being hungry – it makes your fat stores more easily accessible.

How stress hormones affect ketosis

Stress hormones are a potential threat to ketosis because they cause an increase in blood glucose, which in turn leads to the release of insulin. The release of stress hormones is, however, a normal physiological process, that occurs every night and is known as the dawn phenomenon [6].

In the early morning, usually between 4 and 8 am, growth hormones, cortisol, glucagon, and adrenaline are secreted. These hormones work together to increase blood sugar levels, which primes us to get up. In healthy people, this increase in blood sugar triggers insulin release, so that the rise in blood sugar is kept in check and hardly measurable. The amount of insulin released is also not a threat to ketosis.

The situation is a bit different in diabetic patients, though. Insulin levels are lower during the night, their stores of sugar (glycogen) in the liver are usually full, and fat from their fat stores are ready for release; add in normal morning stress hormone release and this can lead to quite a dramatic blood sugar increase in the morning. Additionally, because cells in diabetic patients do not respond well to insulin, this glucose is not taken up easily. This is one reason why diabetic patients have high fasting blood sugar levels, and these high levels can indeed interfere with ketosis [7].

Long-term, a ketogenic diet helps to improves insulin signaling in diabetic patients, which then leads to a less pronounced Dawn phenomenon.

Is the ketogenic stressful for women?

Women are more sensitive to environmental conditions than men are, in some respects. It arises from the need to more readily sense when the conditions are right to have a baby, an essential survival skill. Stressors are thus capable of affecting a woman’s reproductive functions. Stress can cause irregular menstruations and can even negatively affect fertility. Indeed, influencers like Sarah Balantyne and Chris Kresser advise women not to go ‘too low-carb’.

So, is a ketogenic diet stressful for women and does is affect female hormones?

No. Whether you’re male or female, once keto-adapted, a ketogenic diet does not cause stress per se. Dramatic weight loss, however, leads to a decrease in estrogen and may cause anovulation and irregular menstruation [8]. Many overweight women follow a ketogenic diet to lose weight and typically also severely restrict calories. This, of course, is stressful and counterproductive.

Estrogen is an essential female reproductive hormone, which requires sufficient fat intake. For this reason, a diet that is high in healthy fats leads to an increase in estrogen levels [9]. On a ketogenic diet, a lot of fat is, however, used for ketone production. There is another mechanism by which low calorie-diets affect female reproductive hormones: calorie restriction causes a drop in thyroid hormones [10], which in turn may affect estrogen levels.

A systematic review showed that low-carb diets increase fertility in overweight and obese women [11]. Low-carb diets improve menstrual regularity and even pregnancy rates.

This is another lesson in why fat-loss through keto is not all about ketone levels or caloric balance: what matters is that you choose foods that normalize your appetite and give you energy. We shouldn’t leave the table hungry, that defeats the purpose of a nourishing meal.

To summarize: a ketogenic diet is not stressful for women, but caloric restriction certainly can be.

How stress hormones impact body fat levels

Does stress make you fat? Actually, stress hormones such as cortisol promote the release of fats from fat tissue. Again, to provide extra energy which is needed in stressful situations. This promotes the breakdown of stored body fat and should thereby facilitate fat-loss [12].

However, stress hormones instead have the reputation to interfere with fat-loss and make you gain weight [13]. How come? Well, it depends on the context [14].

The fats that are released in response to stress are intended to provide energy. But what else can happen if the stress is chronic? Then these hormones can change the sensitivity of different fat tissues to insulin in such a way that you become more likely to store fat whatever you eat [15]! This is why stress is such a common problem for fat-loss, everyone is susceptible to it.

infographic showing the relation between chronic stress and belly fat storage

Moreover, how you fatten partly depends on what you eat. Fructose is the sugar that got its name from fruit and is commonly added to soft drinks. Fructose can make an enzyme we have called 11β-HSD1 more active [16]. 11β-HSD1 converts the inactive cortisone into the active version of the stress hormone cortisol in our fat tissue. This makes our fat tissue more likely to fatten. This can happen without a stressful trigger, just by eating food that is high in fructose.

Drinking fruit juice or sodas are bad for fat-loss or metabolic health.

In addition to this, fructose is metabolized in the liver, where it leads to the formation of fat, a process called lipogenesis. If at the same time fat cells release fat inappropriately, such as in diabetes, this further contributes to fatty liver development. A fatty liver is strongly associated with insulin resistance and metabolic syndrome, which is why there are so many type 2 diabetics in this cluster of modern chronic diseases [17].

Let’s sum it up: fructose potentiates factors that make us more likely to store fat (even without stress). But if you’re also stressed, then you get a double hit to make you fatter and fatter in a particularly uneahlthy way (in organs besides your ‘belly fat’).

So what can you do to prevent the fattening and metabolic damage from stress? You might have guessed it, but a ketogenic diet is a good start. It’s naturally low in fructose, eliminating a major fattening trigger. Furthermore, it is difficult to overeat while being in ketosis, so the fats that are released from fat tissue in response to stress can be used as fuel instead of being partitioned inappropriately (i.e. to your liver).

Does exercising when keto cause even more ‘stress’? And is it bad?

What about exercise? Strenuous exercise is stressful to the body and triggers the release of stress hormones. It is even said, that for this reason, hard-core exercise can inhibit fat-loss; especially in people who need a lower stress load overall and who are ravenous after exercising.

So what happens during exercise? As other stressful triggers, it leads to an increase of stress hormones. This causes an increase in blood glucose, which is a welcome source of energy during strenuous exercise. So yes, exercise causes stress, which raises blood sugar. However, because that sugar is now being taken up immediately by hungry muscle cells, it is in no way a threat to the general state of ketosis. You’re ketones will lower temporarily, but they’ll start rising again after exercising. Perfectly normal.

Additionally, stress hormones during exercise promote the release of fats from fat storage. Just another welcome source of energy, especially when keto! The benefits of exercising are partially mediated through the action of stress hormones, which is why dose and frequency matter. You’ll rarely overtrain but most of us usually under-rest. So apply that particular stressor intelligently.



How to lower stress levels

  1. As mentioned before, don’t try to severely and intentionally restrict calories when following a ketogenic for fat loss. It just adds stress and is a virtual guarantee way to fail. It is hard to overeat when being in ketosis and when you are overweight, you will likely automatically lose fat. Don’t think you have to eat this or that much because you did or didn’t do something at the gym. If you ‘drink to thirst’ you should also ‘eat till full’.
  2. Follow a well-formulated and nutrient-dense diet, ketogenic diet or otherwise with the help of Nutrita. Whichever of our diets you select, we’ll ensure your brain is well fed for when you start learning anti-stress techniques.
  3. Get enough sleep as sleep deprivation is an incredibly powerful stressor. I don’t just mean not sleeping for 2 days straight, I mean even losing 1-2 hours of sleep multiple times a week. Because sleep quality is highest before midnight, try going to bed early.
  4. Exercise regularly. Even though exercise leads to an acute release of stress hormones, it reduces stress long-term. An short afternoon HIT session is a great way to get the benefit from stress hormones momentarily and the long-term benefit of stress reduction. It also improves sleep apnea [18]!
  5. Have a healthy control over your time as much as possible. In other words, respect the fact that you’re an incredibly social animal and you need to meet those needs (yes, even you introverts). It does not matter how much you enjoy or do or don’t enjoy your work; it is important to take regular brakes and find things that make you want to get up in the morning. Try to spend this time with quality people, or take some time for yourself if that’s what you need.


Contrary to common beliefs, a ketogenic diet is not a stressor. A well-formulated ketogenic diet is incredibly energy- and nutrient-dense and provides anything your body needs: that’s the exact opposite of stress! And with the help of Nutrita it’s dead easy.

A common mistake is that people who use a ketogenic diet to lose weight consciously restrict calories. Severe calorie restriction is indeed a stress factor, but neither necessary nor recommended on a ketogenic diet. Because the keto diet regulates hunger, you can ‘eat till full’ and still lose weight. This is the right way to do it and does not create any kind of stress.

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Written by Sarah Neidler, PhD

Sarah Neidler did her PhD in cancer research at the Beatson Institute for Cancer Research in Glasgow. She has a strong interest in nutrition and the ketogenic diet and believes that they are beneficial for the treatment and prevention of chronic conditions, such as heart disease and diabetes. She loves cooking, reading, sewing, Yoga, and CrossFit.