Stress is a natural response of the body to challenges or threats.
From a biological perspective, it can be described as an adaptive mechanism that allows the body to respond to changes in the environment. This process is regulated by the nervous and endocrine systems, which prepare the body for action through the fight or flight response. Key elements in this process include:
- The sympathetic nervous system, which activates the body to respond.
- The hypothalamic-pituitary-adrenal (HPA) axis, which controls the release of stress hormones such as cortisol and adrenaline. This part of the endocrine system helps the body cope with stress (Lu, Wei & Li, 2021).
Psychology views stress as a subjective experience related to environmental demands that exceed an individual’s coping abilities. There are many theories of stress, but one of the most well-known is the stress theory developed by Richard S. Lazarus and Susan Folkman. According to Lazarus and Folkman, stress is a dynamic interaction between the individual and the environment. This model includes two main stages of evaluation:
Primary appraisal – the individual evaluates whether the situation is:
- Neutral – it has no impact on the person’s well-being.
- Positive – it may bring benefits or new opportunities.
- Negative – the situation is perceived as a threat, challenge, or harm/loss:
- Threat – the situation may lead to future harm or loss (e.g., fear of an exam that could affect academic success).
- Challenge – the situation requires effort and resource mobilization but offers a chance for growth and development (e.g., entering a competition that may improve skills).
- Harm/Loss – the person has already experienced damage or negative consequences (e.g., job loss, breakup, death of a loved one).
2. Secondary appraisal – the individual evaluates their coping resources, including:
- Available social support,
- Possibilities for solving the problem,
- Adaptive skills (Obbarius et al., 2021).
INTERACTIVE ACTIVITY 14
Coping with stress refers to conscious and unconscious actions taken to reduce the tension caused by stress. It may include both problem-solving efforts and strategies for regulating emotions.
1. Coping strategies – individuals use various mechanisms to manage stress levels. There are two main ways of coping with stress:
- by solving the problem that caused the stress, or
- by calming down and managing their emotional response.
- Problem-focused coping – this strategy involves taking action to solve the stressful situation or to change its cause.
- It includes identifying the problem, analysing possible solutions, and taking steps to reduce the stress.
- Example: A person who feels stressed before an exam prepares by studying and organizing their materials.
- Emotion-focused coping – this strategy involves managing the emotions related to the stressful situation, without directly changing the problem itself.
- It focuses on reducing negative emotions such as anxiety or frustration, using relaxation techniques or reinterpreting the situation.
- Example: A person who has experienced a difficult situation practices breathing techniques, meditates, or talks to loved ones for emotional support.
3.1. The Role of Neurotransmitters in Stress Response
The table below lists the main neurotransmitters involved in the body’s response to stress
| Neurotransmitter | Description |
| Adrenaline and Noradrenaline | Synthesized by the adrenal glands and the sympathetic nervous system. Prepare the body for the fight or flight response by increasing heart rate, blood pressure, and blood glucose levels. |
| Dopamine | Responsible for motivation, reward, and the feeling of satisfaction. Under stress, its levels may increase or decrease, affecting mood and behaviour. |
| Serotonin | Regulates mood, sleep, and appetite. Stress can lower its levels, increasing the risk of depression and anxiety. |
| GABA (Gamma-Aminobutyric Acid) | The main inhibitory neurotransmitter, which reduces nervous system activity. Low GABA levels during stress lead to increased tension and excitability. |
| Glutamate | The main excitatory neurotransmitter, which increases neuronal activity. Overactivation under stress may lead to neurotoxicity and cognitive problems. |
INTERACTIVE ACTIVITY 15
| References |
| Obbarius, N., Fischer, F., Liegl, G., Obbarius, A., & Rose, M. (2021). A modified version of the transactional stress concept according to Lazarus and Folkman was confirmed in a psychosomatic inpatient sample. Frontiers in Psychology, 12, 584333. https://doi.org/10.3389/fpsyg.2021.584333 Lu, S., Wei, F., & Li, G. (2021). The evolution of the concept of stress and the framework of the stress system. Cell Stress, 5(6), 76–85. https://doi.org/10.15698/cst2021.06.250 Knezevic, E., Nenic, K., Milanovic, V., & Knezevic, N. N. (2023). The Role of Cortisol in Chronic Stress, Neurodegenerative Diseases, and Psychological Disorders. Cells, 12(23), 2726. https://doi.org/10.3390/cells12232726 |
3.2. Eating habits under stress
Stress is a significant factor influencing human behaviour, including eating habits.
It affects food choices through both biological mechanisms and behavioural changes. Research has shown that stress can disrupt normal eating behaviours, often leading to increased consumption of unhealthy foods and reduced intake of nutritious ones (Hill et al., 2022). This module examines the relationship between stress and dietary habits, incorporating findings from recent studies and meta-analyses.
How does stress affect the appetite?
Stress is common in daily life and can influence health, including changes in appetite. One study examined how acute stress affects appetite in healthy, non-obese men during fasting.
Acute stress refers to a sudden and short-term reaction to a difficult situation, such as public speaking or solving a challenging math problem.
In the experiment, participants performed stressful tasks and then viewed images of food while their brain activity was recorded. The results showed that stress increased nervous system activity but at the same time suppressed appetite. This effect was linked to changes in the front part of the brain (known as the frontal pole).
These findings suggest that stress can reduce feelings of hunger, particularly when it is related to anticipation of a difficult event (Nakamura et al., 2020).
To better understand this phenomenon, researchers conducted a meta-analysis of several scientific studies aiming to estimate the strength of the relationship between stress and eating in healthy adults, and to identify factors that might modify this association. The analysis included only studies in which stress was clearly defined as a negative environmental event (rather than an emotional state), and which assessed eating behaviours unrelated to eating disorders.
The results showed a small but statistically significant relationship between stress and overall food intake. Stress was associated with an increase in the consumption of unhealthy foods, while simultaneously reducing the intake of healthy foods. This suggests that under stress, people are more likely to choose high-calorie foods rich in sugar and fat, while cutting back on foods considered beneficial for health.
Analysis of potential moderating factors revealed that dietary restraint was the only significant moderator. Individuals who followed a restrictive approach to eating responded differently to stress, particularly in terms of unhealthy food consumption.
Although the effect of stress on eating habits is small, its consequences may be important for public health. Increased intake of unhealthy foods combined with reduced consumption of healthy options may, over time, contribute to the development of metabolic diseases and other health problems. Further research is needed to identify factors that influence this relationship, especially those that differentiate between the intake of healthy and unhealthy foods (Hill et al., 2022).
People who experienced stress more frequently and went through negative life events had stronger cravings for tasty but unhealthy foods. They also had more difficulty controlling the amount of food they consumed. This suggests that some individuals are more vulnerable to the effects of stress on eating behaviour.
Additionally, the study found that stress influenced eating habits even in the short term. On days when adolescents felt more stressed than usual, they were more likely to eat in response to difficult emotions. In other words, not only the overall level of stress in a person’s life matters — daily fluctuations in stress levels can also affect food choices.
The findings show that stress can lead to unhealthy eating habits in young people. This relationship may differ depending on whether we examine a person’s general level of stress or short-term, day-to-day changes. Further research is needed to better understand how stress affects eating behaviour and why some people are more sensitive to its effects than others (Hsu & Raposa, 2020).
Why do some people eat more under stress, while others eat less?
Not everyone responds to stress in the same way. Some individuals – so-called “emotional eaters” – tend to eat more, especially unhealthy foods, to improve their mood. Others lose their appetite when stressed.
Research suggests that the hormone ghrelin may play a key role in this difference. People who experience increased appetite under stress often have lower resting levels of ghrelin, which may lead them to seek out high-calorie foods in order to feel relief (Sominsky & Spencer, 2014).
Hormones, stress, and eating
- Leptin – reduces appetite, but chronic stress may lead to leptin resistance, which can result in overeating.
- Ghrelin – known as the hunger hormone; its levels increase during stress, encouraging food intake.
- Peptide YY (PYY) – reduces appetite, but its levels may be disrupted under stress. (Ans et al., 2018)
Chronic stress and weight gain
When a person is exposed to stress over a long period, the body produces increasing amounts of cortisol. This can lead to increased appetite, fat accumulation, and a higher risk of overweight. Chronic stress is also associated with metabolic diseases such as type 2 diabetes. However, it is important to note that in some cases, chronic stress may lead to reduced appetite, particularly in individuals with a tendency toward depression (Sominsky & Spencer, 2014)
INTERACTIVE ACTIVITY 16
| References |
| Ans, A. H., Anjum, I., Satija, V., Inayat, A., Asghar, Z., Akram, I., & Shrestha, B. (2018, July 23). Neurohormonal regulation of appetite and its relationship with stress: A mini literature review. Cureus, 10(7), e3032. https://doi.org/10.7759/cureus.3032 Hill, D., Conner, M., Clancy, F., Moss, R., Wilding, S., Bristow, M., & O’Connor, D. B. (2022). Stress and eating behaviours in healthy adults: A systematic review and meta-analysis. Health Psychology Review, 16(2), 280–304. https://doi.org/10.1080/17437199.2021.1923406 Hsu, T., & Raposa, E. B. (2021). Effects of stress on eating behaviours in adolescents: A daily diary investigation. Psychology & Health, 36(2), 236–251. https://doi.org/10.1080/08870446.2020.1766041 Nakamura, C., Ishii, A., Matsuo, T., Ishida, R., Yamaguchi, T., Takada, K., Uji, M., & Yoshikawa, T. (2020). Neural effects of acute stress on appetite: A magnetoencephalography study. PLOS ONE, 15(1), e0228039. https://doi.org/10.1371/journal.pone.0228039 Sominsky, L., & Spencer, S. J. (2014). Eating behavior and stress: A pathway to obesity. Frontiers in Psychology, 5, 434. https://doi.org/10.3389/fpsyg.2014.00434 |
