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The Science Behind Stress, Food and Weight management

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, 7 min read

The Science Behind Stress, Food and Weight management

In the modern world, stress has become ever more present in all parts of life. It varies in intensity and frequency and can have a significant effect on physical and mental health. It can weaken the immune system, increase the risk of cardiovascular diseases and exacerbate existing health conditions. Stress can also lead to unhealthy coping behaviours. Understanding the science of stress and in particular our diet could help us to address associated poor health outcomes. 

Types of stress

Stress can be categorised into two main types: eustress and distress. Eustress, often referred to as ‘good stress.’ is the type of stress that can be perceived as positive or motivating. It typically arises from situations that are perceived as challenging but manageable, such as preparing for an interview, starting a new job or competing in a sport.

Distress, on the other hand, is the negative type of stress that is often associated with fear, anxiety, or feelings of overwhelm. It arises from situations that are perceived as threatening, harmful, or beyond one’s ability to cope, such as traumatic events, financial difficulties or a relationship breakdown. 

Understanding the differences between these two types of stress is crucial because they can have distinct effects on our physical and mental health. Eustress can be beneficial in helping to improve focus, motivation, and performance, while distress, if not managed properly, can lead to various health problems, including anxiety disorders, depression, and physical illnesses. 

Read more: 10 Ways to Reduce Stress and Improve Well-being

HPA and the SAM

The Hypothalamic-pituitary-adrenal (HPA) axis is involved in the body’s stress response. The HPA axis releases cortisol to give the body energy and alertness in response to a challenge, but it should return to normal levels once the stressor is gone. Prolonged elevation of cortisol due to chronic stress can lead to negative effects on the body, including impaired immune function, weight gain, high blood pressure and increased risk of certain health conditions like heart disease and diabetes.  

The sympathetic-adrenal-medullary (SAM) axis also plays an important function in response to stress. When the brain perceives a stressor, it signals the sympathetic nervous system to activate the release of adrenaline and noradrenaline into the bloodstream. These hormones increase heart rate, blood pressure and respiration, preparing the body for a fight or flight response to the perceived threat. Sensitivity to distress can be influenced by a variety of factors, including past experiences, the duration and intensity of the stress, your environment, and frequency of exposure to stressors.

The relationship between stress and eating

Cortisol can influence food cravings, particularly for high-calorie or high-value foods that are rich in sugar, fat and salt. This is because cortisol can stimulate the brain regions associated with reward and pleasure, making these types of food more appealing during times of stress. Cortisol can also affect appetite-regulating hormones, which further contribute to increased hunger and cravings for energy-dense foods. Over time, high levels of glucose in the bloodstream as a result of cortisol in the body along with high sugar foods can contribute to insulin resistance and increases the risk of developing type 2 diabetes. Cortisol can also impair the action of insulin, the hormone responsible for regulating blood sugar levels, further exacerbating the risk of diabetes.

Our ability to deal with food is also linked with stress. Adrenaline turns off the digestive system so that energy and resources are concentrated to other body systems in preparation to react to stress. It makes sense therefore that stress can contribute to weight gain as the body is not able to break down food effectively and can cause digestion related issues. Eating in response to stress (emotional eating) is more likely if you experience stress as a fear rather than a challenge because cortisol (the distress hormone) stimulates. 

Parasympathetic nervous system

The parasympathetic nervous system ‘downregulates’ the body and brain. The vagus nerve sends impulses from the brain to the body and vice versa so that your brain knows what’s happening, instead of just your body reacting to the brain. When this parasympathetic system functions well, it will increase digestion which improves gut issues such as IBS symptoms for example. This is because the parasympathetic system promotes relaxation and the stress response so that the stress response is no longer active. Cortisol is lowered which induces a calmer state of mind.

Stress and food

We now know that reaching for the wrong food, eating too much or too little is a matter of science, rather than behaviour.  The food you eat directly affects the processes in your body, and can either add to stress or help you to manage it.

Foods that reduce stress

  • Protein – The hormones and neurotransmitters that make up your stress response systems are made from the amino acids you get from protein. Deficiencies as a result of a lack of protein therefore can impact the way your brain functions. Fatty fish are a great source of protein as well as lean meat such as chicken. For vegetarians and vegans you can eat tofu and beans to hit your protein goal.
  • Tea – L-theanine is an amino acid that produces a calming effect due to the support it provides to the chemicals in the brain that reduces anxiety. L-theanine is found in green, chamomile and peppermint tea.
  • Probiotic, prebiotic and fermented food – One of the key mood-boosting hormones is made in your gut and probiotic and fermented foods help to keep the bacteria in your digestive system balanced. Foods like Greek yoghurt, kombucha tea and sauerkraut all naturally promote a healthy gut. Probiotic foods contain other components that help protect the bacteria in the gut. For example, a dairy portion of yoghurt can help to protect the bacteria from your stomach so that it can survive long enough to get to your large intestine. High fibre foods like fruits, veggies, whole grains, beans and legumes contain “prebiotics,” which also feed the healthy bacteria in your GI tract.
  • Magnesium – Leafy green vegetables, salmon and dark chocolate contains magnesium which is shown to help with sleep, which is very important for recovery from stress.
  • Vitamin D - Research shows a correlation between vitamin D deficiency and stress. It is also essential for your immunity, which, being ill can cause stress. Vitamin D is found in dairy products such as eggs and cheese, fatty fish and mushrooms.

A lack of nutrient rich foods also puts additional strain on the body to keep itself running as it should. Also, your body has to manage substances that cause certain organs to work harder.

Foods that increase stress

  • High sugar – the body needs to work hard to regulate food high in sugar. Your body has to make insulin to help manage the rapid increase in sugar and the ‘crashing period’ has an impact on the amount of cortisol that is released leading to a state of fight or flight. In addition, if there is too much sugar in the blood this can become thick which makes it harder for your heart to pump the blood around the body. This causes more strain on the body to correct it.
  • Fried foods – This includes foods that are high in trans fats, which indirectly cause inflammation. Trans fats are harder for the body to break down, therefore the body wouldn’t use these types of foods immediately as fuel. Instead the body will store them which requires more work for the body. 

There are a number of ways that we can manage stress levels, and diet plays a crucial role. Our eMed Weight Management Programme provides a wrap around approach, including supporting you with exercise, diet and nutrition, to make lost-lasting change to support your health and wellbeing. Our eMed CBT Therapy service also offers support for managing stress and developing coping mechanisms for difficult situations.

Read more: What Foods Are Good For Weight Loss?

The information provided is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Seek the advice of a doctor with any questions you may have regarding a medical condition. Never delay seeking or disregard professional medical advice because of something you have read here.

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