The influence of diet on stress and blood cortisol levels

Translated by: Avramov Maxim - an enthusiast of a healthy lifestyle and author of the website ilovemysport.ru.
2020-02-13

Is it true that diets deplete the body, leading to increased cortisol levels in the blood? Or perhaps you experience stress due to decreased body fat? Let’s find out together.

What does cortisol do?

Cortisol is the stress hormone. Its two main functions are: fight or flight. This is how our body reacts to dangerous situations: when you are attacked by a criminal or face a survival threat.

Most of us encounter life-or-death situations only during games or while watching movies and series. However, we still feel stress at work or school, as well as from lack of sleep.

Cortisol is produced by the adrenal glands. This hormone is responsible for metabolism. Usually, to obtain energy, our body uses carbohydrates, then fats, and finally amino acids from muscles. But cortisol derives energy from muscles and glycogen. Fat is not utilized because it requires more time and energy expenditure.

High cortisol levels in the blood can lead to increased blood pressure (also called arterial pressure), blood glucose, insulin resistance, decreased libido, and even chronic diseases such as metabolic syndrome and type 2 diabetes. Insomnia and poor memory are also common side effects. To reduce the risk of developing type 2 diabetes, you need to consume enough fiber.

On the other hand, low cortisol levels in the blood can be harmful. This can lead to body fatigue, loss of appetite, and low blood pressure.

How to maintain normal cortisol levels?

To keep cortisol levels normal, we need to manage our stress levels. However, this is where the catch lies. 80% of an athlete’s success depends on sticking to a diet. But that very diet can also be the culprit for stress.

In 2010, a study titled “Low-Calorie Diet Increases Cortisol Levels” garnered media attention. Many publications blamed cortisol not only for a lack of progress in working weight and subsequent depression but also for any positive effect from such a diet in general.

The most effective diet is one that causes a caloric deficit. Therefore, you should consider the impact of this restriction on your cortisol levels.

It’s also important not to forget about body mass and fat levels. When the body triggers a protective reaction to stress, both of these factors influence cortisol levels.

And finally, one should not forget the psychological aspect of this issue. It’s challenging for people to commit to a diet. Making such a decision can also cause stress. This, in turn, will increase cortisol levels in the blood.

Caloric restriction and cortisol

We have already established that low-calorie diets negatively affect cortisol. But the flip side of the coin exists. Fasting increases cholesterol and triglycerides, whereas low-calorie diets do not.

Although this conclusion contradicts previous results, it is essential to note that it is based on the acute reaction of the body to caloric restriction. According to one study, a two-year caloric restriction did not result in increased cortisol levels in the blood. However, to be fully confident in this, more long-term testing is required.

For example, reducing caloric intake over a short period has different effects on the body compared to the long term. This is not so much of a concern for us in daily life, but it could become a problem for athletes, bodybuilders, and those on a diet for several months or years.

Despite this, there is no substantial evidence that caloric restriction raises cortisol levels in the blood. Moderate caloric restriction has been shown to reduce not only inflammation but also its markers, such as CRP and TNF-alpha. However, further research is needed to determine what exactly moderate caloric restriction means and how the duration of this restriction affects inflammatory processes.

Reducing caloric intake positively influences health. It increases markers of longevity and benefits the functioning of skeletal or striated muscles. When considering caloric restriction in isolation, you realize that a diet should not be a stressor for the body.

If you are on a low-calorie diet and wish to lower your “bad” cholesterol, you should learn more about the benefits of avocados.

The Influence of Cortisol on Body Weight and Body Fat

While studies indicate the benefits of limiting daily calorie intake, the problem lies in low body weight and fat levels. These factors become particularly relevant if you are on a diet.

In fact, people with excess body weight tend to have the lowest cortisol levels in their blood, whereas those who are obese or underweight exhibit the opposite. Individuals who are underweight often have the highest cortisol levels, and they are also prone to increased levels of this hormone immediately upon waking from sleep.

In other words, caloric restriction itself from a diet does not raise cortisol levels in the blood. However, low body weight and fat levels completely change the situation.

The activation of the hypothalamic-pituitary-adrenal (HPA) axis, our central stress response system, is linked to the aforementioned factors. The inverse relationship between body mass and body fat explains why we feel exhausted after being on a diet for an extended period.

The hypothalamic-pituitary system is a combination of the pituitary gland and hypothalamus. They are responsible for the nervous and endocrine systems. Stress is perceived by the cerebral cortex. From there, an impulse is sent to the hypothalamus, where corticotropin-releasing hormone (CRH) is produced. This stimulates pituitary receptors, leading to the secretion of corticotropin into the plasma, which in turn activates corticotropin receptors in the adrenal cortex. Thus, cortisol enters the bloodstream.

The benefits of restricting daily caloric intake should be viewed in the context of your body's state. If you have a high level of body fat, a diet will help you. However, for individuals who are quite thin, this approach can be harmful and intensify their stress response. All of this can lead to undesirable health consequences.

Psychological Aspects of Being on a Diet

A diet is more than just a restriction of calories or a pursuit of lower body fat. People want to lose weight. Some prefer to say they are dieting while not actually doing it. Others simply watch what they eat.

Each person who is on a diet has their own reason for wanting to lose weight. Some start monitoring their weight after biting comments from colleagues or friends. Others buy a gym membership in the winter to ensure they lose weight by summer. And some do it for medical reasons. Weight loss can lead to improved well-being, normal blood pressure, and increased testosterone levels in men.

The psychological aspects of a person's body image or their perception of dieting can become a stressor, regardless of whether they adhere to the diet or not. Athletes, health enthusiasts, and those dissatisfied with their body keep track of their health. But they also often find themselves on a diet, which can be an emotional strain. The very mindset and choice of diet can elevate cortisol levels in the blood. Thus, the body triggers a reaction to external stressors.

When discussing the psychological characteristics of a person on a diet, it is essential to consider gender differences. Men often pay less attention to their health. Why should a macho man concern himself with such trivial matters? Dieting is more common among women. Consequently, the effects of caloric restriction can differ between men and women.

Researchers are studying the connection between diet and stress, but it is already evident that this involves not only physiological aspects but also psychological perceptions of the situation. The greater the influence, the higher the cortisol levels in the blood. It is important to take a simpler approach. Reduce physiological and psychological stress situations. Let each meal or training session bring joy rather than becoming an exhausting ordeal.

Conclusion

Approximately 42% of adults worldwide attempt to lose weight. A diet can either help or harm the body. It all depends on the current situation. Consider body weight, fat levels, past diets, and overall health when making dietary changes. Always consult with a doctor before making significant changes to your diet.

Repeated dieting can have negative consequences for health. It can increase blood pressure, heart rate, glucose levels, lipids, and insulin.

Follow a balanced diet. This way, you’ll be able to control cortisol levels and overall stress. Engage in physical activity, get enough sleep, relax with friends and loved ones, and spend more time outdoors. This will improve your mood and lower cortisol levels in the blood.

Translation of an article from Muscle & Strength.