The connection between stress, cortisol levels and weight gain

Key takeaways

• When you're stressed, your adrenal glands release cortisol, the "stress hormone," which helps your body respond to stress. Elevated cortisol levels can lead to weight gain, particularly around the midsection.
• High cortisol levels can slow down metabolism, decrease muscle mass, and promote the storage of fat. Stress also influences food choices, often leading to emotional eating, especially high-sugar, high-fat foods.
• Reducing stress through methods like exercise, mindfulness, improved sleep, and healthier eating habits can help lower cortisol levels and support weight loss.

Stress can be pretty, well, stressful for your body. Whether it’s acute or chronic, stress has the potential to cause all kinds of issues, like gastrointestinal problems, musculoskeletal pain and a higher risk of heart attack and stroke, among many others [1].

One of its main impacts is the increased production of cortisol, AKA the ‘stress hormone’, which also happens to be linked to weight gain [2].

But how exactly does the relationship between stress, cortisol and weight gain work? Here’s what you should know.

What is cortisol?

Cortisol is a hormone produced by your adrenal glands. You have 2 of these glands, which sit above each kidney. Your pituitary gland, which is located at the base of your brain, controls how much cortisol gets released by your adrenal glands.

You’ve probably heard cortisol referred to as the ‘stress hormone’. This is because one of its primary roles is to support your body’s stress response. It does this by providing energy to your body and suppressing non-essential bodily functions (like your digestive and reproductive systems) during a fight-or-flight situation.

But, cortisol actually has a lot of other crucial jobs [3][4]. These include:

• Helping your body metabolise glucose
• Moderating blood pressure and blood sugar
• Curbing inflammation
• Supporting your immune system.

What do healthy cortisol levels look like?

Your body is designed to maintain healthy cortisol levels. But these levels aren’t actually consistent. 

When they’re functioning normally, your adrenal glands produce varying amounts of cortisol across the day according to your energy needs. In the morning — between 6am and 8am — your cortisol levels are usually at their highest, before dropping across the rest of the day. They’re at their lowest around midnight [5].

So, that means healthy cortisol levels can look different depending on the time of day (as well as the type of test used and the person being tested). But in most cases, normal ranges of cortisol levels are:

• 6am-8am: 10-20 micrograms per decilitre
• 4pm: 3-10 micrograms per decilitre [6].

What are the symptoms of high cortisol levels?

Increased cortisol levels often come about as a result of chronic stress.

But they can also be caused by pituitary gland issues, tumours on the adrenal glands and medications — usually corticosteroid medications, which are anti-inflammatory drugs used for all kinds of conditions including rheumatoid arthritis.

Aside from the results appearing on a test, there are a few tell-tale signs of high cortisol levels [4][7]. These include:

• Weight gain, especially around the midsection and face
• Fatty deposits at the back of the neck
• Thinning skin
• In females, excess hair, particularly on the face
• Irregular periods
• Acne
• Fatigue
• Mood swings

What do low levels of cortisol do to the body?

On the flip side, cortisol levels can also be too low. There are several reasons for this, but the most common is abruptly stopping corticosteroid medications after taking them for an extended period.

Doing so can result in adrenal insufficiency, where either your adrenal or pituitary glands struggle to produce enough cortisol [9].

Addison’s disease — where the adrenal glands are damaged and aren’t producing enough cortisol and aldosterone as a result — is another cause of low cortisol levels, but it’s fairly uncommon [10].

Low cortisol levels affect the body in many ways, causing muscle weakness, weight loss, low blood pressure, low libido, low appetite and chronic fatigue [9].

What's the link between cortisol and weight gain?

We know that stress can raise cortisol, which can lead to weight gain. But how exactly does this happen? 

Excess cortisol affects certain bodily functions related to weight maintenance. For one, it can slow down your metabolism, which we know helps regulate body weight. It can also decrease muscle mass, as it hampers testosterone production.

There are some other effects that stress and cortisol can have on your weight, including:

Promoting overeating

Studies have found conflicting reports on the effects of stress on appetite. Some have concluded that a stressful situation can decrease appetite and others that there’s no difference in food intake [11].

But there are a few studies that discovered that participants ate more during stressful periods — which we often refer to as 'emotional eating'.

As well, a 2015 survey by the Australian Psychological Society found that 75% of Australians turned to food as a way to cope with stress [12]. Obviously, increased food intake can result in weight gain, which means some people may be more likely to put on weight as a result of high stress levels.

Stress has also been linked to food noise, a persistent mental preoccupation with food that can often lead to overeating and, consequently, weight gain. This is especially true for those who are prone to ‘emotionally eat’ and who, during periods of heightened stress, may find themselves constantly seeking the comfort of food.

Creating sleep hygiene problems

Some studies have found a pretty clear link between high cortisol levels and poor sleep — whether through making it hard to fall or stay asleep or sleeping for less time. Research has also shown that broken sleep can further increase cortisol levels, creating a vicious cycle of insomnia [14].

There seems to be a connection between sufficient sleep and healthy body weight, with research showing that a lack of sleep can lead to weight gain [15].

This is because not getting enough sleep raises levels of the hormone known as ghrelin (responsible for increasing appetite) and lowers levels of leptin (which helps you feel full). Inadequate sleep can also bring on poor food choices [16].

Cortisol-induced weight gain typically shows up around the midsection (this can be referred to as a 'hormonal belly').

It’s worth noting that issues related to elevated cortisol levels typically come about when stress is ongoing, or chronic. A brief stressful event is unlikely to create long-lasting problems.

How do I lower cortisol levels and lose weight?

If excess cortisol seems to be the reason behind your weight gain, you’ll be glad to know that the issue can most definitely be addressed.

Your first port of call should be a medical professional, such as your GP, who can look at any underlying causes of high cortisol levels. There may be a medical link, such as problems with your pituitary gland.

There are also several lifestyle and habit changes you can implement to restore your cortisol levels to a healthy range and, eventually, lose weight.

Reduce your stress levels

The most important part is curbing your stress, because we know there’s a link between chronic stress, elevated cortisol and weight gain.

The best methods for managing stress include getting enough sleep, moving your body (bonus: regular exercise is another great way to maintain or lose weight!), sticking to a healthy diet, practising mindfulness and connecting with others. You can also try positive affirmations, breathing exercises or listening to music [18].

If you need help with stress management, don’t hesitate to contact a mental health professional.

Practise mindful eating

Mindful eating means being more conscious of the foods you choose and responding to internal and external cues that tell you when you’re satisfied [19].

So, instead of reaching for sugary or fatty foods when you’re stressed, you could go for something more nutritious — like a piece of fruit or a handful of raw nuts — instead. 

Alternatively, see if you can find another way to deal with a stressful situation, such as one of the stress-busters we mentioned earlier.

Improve sleep hygiene and sleep debt

By improving your sleep, you may be able to reduce your cortisol levels and, consequently, your weight. To improve your sleep hygiene, there are a few good habits you can implement.

These include being consistent about when you go to bed and get up; working out during the day; keeping daytime naps short; getting rid of electronics from your bedroom; creating a dark, cool and quiet sleeping environment; and steering clear of big meals, alcohol and caffeine close to bedtime [20].

Try a holistic weight loss program

A holistic weight loss program can also be hugely beneficial. Juniper’s Weight Reset Program takes a multipronged approach to weight management — get treatment that targets weight gain on a biological level, plus a dietitian-led program that supports long-term weight maintenance.

By joining the program, you’ll have everything you need to restore your cortisol levels to a healthier range, lose weight and create good habits to keep your health in check for the long haul.