Can Stress Affect Body Weight?

Stress affect your physical and mental health and can lead to behavioural changes. Prolonged stress can cause changes in your body weight.

Everyone experiences stress from time to time. Relationships, work, finances, and life changes can all cause stress as can too much exercising and constantly rushing from one thing to the next. Stress affects almost every area of the body and some of the effects it has on bodily systems and processes can cause weight changes.

Gastrointestinal Distress

Stress affects the communication between the brain and gastrointestinal (GI) system, making GI symptoms more apparent, because stress affects all parts of the GI system, including the oesophagus (food pipe), stomach, and bowel. Symptoms can include:

        • heartburn or reflux
        • difficulty swallowing
        • gas/bloating
        • abdominal pain
        • nausea/vomiting
        • increased or decreased appetite
        • diarrhoea
        • constipation
        • muscle spasms

Stress Hormones

When the body is under stress, your sympathetic nervous system kicks into action releasing adrenaline and cortisol into your bloodstream. Adrenaline increases the heart rate and blood pressure, and cortisol releases fatty acids and glucose. Known as the fight or flight response, this happens so you have energy to escape from a risky situation. 


Once the threat has subsided your adrenaline high wears off and your blood sugar spike drops so, cortisol kicks into high gear to replenish your energy supply. However, the body does not differentiate between life threatening and non-life-threatening situations. Therefore, the biochemical response to stress is the same whether you’re about to be hit by a bus and need to move quickly, or you’re looking at the 100 new emails in your inbox that all need urgent attention.

Cortisol and Sugar Cravings

Sugar supplies your body with quick energy, so it is often the first thing you reach for when you are stressed. When you’re stressed and reach for that quick fix, you end up with excess sugar (which as been converted into glucose) in your blood stream and all that glucose in your system needs to go somewhere (unless you used it to escape being hit by the bus). Consequently, it get stored.


Firstly it is stored in you muscles and kidney as glycogen ready for the next emergency.

Secondly, when the muscles and liver are at capacity, glucose is stored in your fat cells, and it’s mainly stored in abdominal fat.


And so the vicious cycle starts: get stressed, release cortisol, gain weight, crave more sugar, eat more sugar, gain more weight.

Cortisol and Metabolism

Even if you are not eating foods high in fat and sugar, cortisol slows down your metabolism, making it difficult to lose weight.


Cortisol is a long-term stress hormone and for thousands of years the only long-term stress humans encountered were drought, famine, and war. During these times, food was scarce, and it made sense the metabolism was slowed so we did not spend as much energy. Our present-day long-term stresses are likely to be financial, relationship or uncertainty about the future.


Here is the problem: our metabolism is slowed for the perceived impending famine, but there is plenty of food available. Some of the food we eat is used however, due to our slower metabolism, we do not need as much, so the remainder gets stored and it gets stored as fat – again, around our middle section.

Stress-Induced Unhealthy Habits

In addition to hormonal changes related to stress, stress can also drive you to engage in unhealthy behaviours.

  • Emotional eating: Excess nervous energy can often cause you to eat more than usual.
  • Eating “accessible” or fast food: When you are stressed, and not planning, you tend to eat the first thing you see and/or what is readily available and accessible.
  • Exercising less: Exercising may be the last thing on you list of things to do when you have high demands on your schedule,
  • Skipping meals: Skipping breakfast or missing lunch is easy when you’re running late or just have too much to do.
  • Sleeping less: Many people report trouble sleeping when they are stressed and research has linked sleep deprivation to a slower metabolism. Feeling overtired can reduce willpower and contribute to unhealthy eating habits.

How to Break the Cycle of Stress and Weight Gain

When you are stressed, healthy behaviours likely eating properly and exercising regularly are easily forgotten. Maintaining a schedule or routine can help make these healthy behaviours a habit and, as a result, combat stress-related weight changes.

  • Make exercise a priority: Exercising is a critical component of stress reduction and weight management, but there is no need for strenuous gym workouts or high intensity cardio work. A gentle walk in nature, yoga or tai chi is a great for stress relief.
  • Eat healthier comfort foods: You do not need carbs or fats to make you feel better. Snacking on unsalted nuts and seeds or vegetable sticks and hummus, for example is ideal. Salads and quick cooking greens are perfect. If you can afford it, try a food delivery service where recipes and all the necessary ingredients are delivered to your door. Saves you thinking what to have for dinner.
  • Focus on what you are eating: Eat mindfully, without distractions. This may help lower stress, promote weight loss, and prevent weight gain. In other words, turn off the TV and electronic devices so you can enjoy your food and the company of those you are with.
  • Drink more water: It is easy to confuse thirst for hunger.
  • Is it life threateningly urgent? Challenge your perception of pressure and urgency. Do you need to do it right now? or can it wait a while.
  • Incorporate stress-relief strategies into your daily life: Whether you enjoy yoga, meditation or reading a book, try adding simple stress relievers. Take a deep breath, listen to music, or go for a walk. Adding these to your daily routine can reduce your cortisol levels, and help you manage your weight.

But most importantly, be kind to yourself. These habits weren’t formed overnight and neither was any weight gain.  

If you are interested in knowing more about how stress affects your body then please get in touch. As a qualified nutritionist, I’m happy to answer any questions you may have

 Bachelor of Science (Biochemistry and Biological Science) University of Canterbury

   Graduate Diploma Human Nutrition, Ara Institute of Canterbury

   Member of the Nutrition Society of New Zealand, Associate Registered Nutritionist