Feeling stressed? That’s not surprising. The modern world, with its relentlessly breaking bad news and always-on communication, is more or less set up to keep us on edge.
But there’s a problem: our bodies are built for fight or flight, not fearmongering and Facebook notifications. We’re increasingly finding that constant and continual stress can be very bad for us – and it’s likely one of the biggest causes behind our worldwide weight gain.
There is some good news, though. Even if the wider world is unlikely to change anytime soon, there are a few simple steps we can take right now to reduce the negative effects of stress on our bodies (see ‘De-stress your life’). But before we take those steps, it’s worth getting an insight into how stress can lead to an expanding waistline.
All stress, no release
The first thing to understand is that sustained or ‘chronic’ stress (to use the technical definition) is a pretty modern invention.
In limited doses, our natural ‘caveman’ response to the sort of sudden stresses we’ve evolved to handle – a sabre-toothed tiger attack, say – is sensible and helpful. Non-essential bodily functions are shut down, a rush of hormones kicks in and our bodies get ready for fight or flight.
Like basically all vertebrates, the core of the human stress response is built around the fact that our muscles are probably going to need to get us out of immediate trouble. So our heart rates go up and our breathing quickens.
Cortisol, which you might have heard referred to as ‘the stress hormone’, is released, bringing glucose, our body’s most readily available source of energy, out of storage in the liver and muscles.
At the same time, long-term bodily functions that won’t help in an immediate crisis – such as muscle repair, our immune system and digestion – more or less shut down. This is where problems kick in if you’re stressed all the time. Your body is always prepared for a physical crisis, so it never has time to do anything else.
Stress enough, then, and your stress response can become more damaging than the stressors themselves.
The problem is that stressors are everywhere in the modern world and usually don’t offer the physical solution – the fight or flight – our bodies are set up for. Everything, from worrying about the mortgage to getting stuck in traffic, can trigger some form of stress response.
Even worse: we can generate stressful events entirely in our own heads, worrying about events that aren’t actually that serious or speculating about what might happen in the future.
When we sit around and worry, we’re turning on the same physiological mechanisms that are designed for short-term crises, and putting the systems used for repair and recovery on hold. And we’re often doing this multiple times a day, for weeks, months or even years on end.
This can have all sorts of unfortunate physical effects, but one that’s becoming better understood recently is that stress can contribute to an increase in weight.
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Stress eating
A 2017 study published in the journal Obesity found that, among more than 2,500 men and women aged 54 and older, exposure to higher levels of cortisol over several months was associated with people being more heavy and more persistently overweight.
“There are basically two pathways connecting stress and obesity in the body,” says Dr A Janet Tomiyama, a professor of psychology at the University of California, Los Angeles, who co-authored one of the most recent papers on stress as it relates to fat storage.
“One pathway is physiological: stress initiates the release of cortisol, which can drive appetite and signal your body to deposit excess energy as fat. The other pathway goes through behaviour – a lot of people want to eat when they feel stressed and the things they eat tend to be higher in calories, sugar and fat. In fact, stress makes your brain feel really rewarded by these kinds of foods.”
If stress is brief and infrequent, this isn’t too much of an issue. When we’re in fight or flight mode, our bodies have more than enough energy to work with, and reduced activity from our digestive systems can decrease our appetites.
It’s when stress is frequent and prolonged that problems start. A 2022 review of studies suggests that stress can act against our interests, affecting our bodies’ levels of the hormones involved in hunger and satiety, including leptin and ghrelin.
High levels of cortisol can also interfere with the body’s production of corticotropin-releasing hormone (CRH), which typically suppresses appetite.
“We don’t know a lot about differences between individuals, but we do know that some people respond to stress by eating more, others by eating less and some don’t change their eating at all,” says Tomiyama. “What we don’t know is exactly how to predict who will fall into each of those categories.”
It’s likely, however, that cortisol is key. In one 2007 study, British researchers demonstrated that test subjects who responded to stress with high cortisol levels were more likely to snack in response to daily hassles than low-cortisol responders.
It might also affect our choice of snack. “We tend to see that people eat ultra-processed foods when they’re stressed,” says mindfulness coach Dr Danny Penman. “They don’t take as much preparation as healthier, more natural foods and they’re easier to grab off the shelf.”
More frustratingly still, stress seems to affect the places fat is stored in the body. You might otherwise be in decent shape, but worrying too much about your pension or the disappearing bees might lead you to carry more weight around your waist.
A 2018 review of the literature points out that “long-term cortisol levels are elevated in obese individuals and seem in particular related to increased abdominal fat mass.”
Though the nature of this relationship might not be entirely one-way (it’s possible that being overweight creates stress rather than resulting from it), there’s other evidence to support the idea that ‘stress belly’ is real.
“The strongest evidence is in Cushing’s disease, which is a congenital illness where your body creates too much cortisol,” explains Tomiyama. “A hallmark symptom of Cushing’s is excess belly fat – that fat goes away when you medically intervene to normalise cortisol levels.”
This is a concern because stored fat around the midriff can be a marker for a host of health problems. Abdominal obesity is more strongly associated with cardiovascular risk factors than overall obesity, including increased blood pressure and type 2 diabetes. It’s also been linked to dementia, asthma and some cancers.
There’s also a possibility that the relationship between stress and fat is somewhat self-sustaining. Putting on weight can cause stress, which in turn can make excess fat harder to shift.
Interventions, big and small
To sum up, then: frequent, long-term stress has a whole host of effects on the body. It can ramp up fat storage and appetite, lead us to worse dieting decisions, and make it harder for us to lose weight.
To make matters worse, weight gain might form a positive feedback loop – elevating our cortisol levels and disrupting other key bodily functions. So what do we do about all this?
“At the individual level, there are lots of interventions we can make,” says Tomiyama. “Mindfulness and cognitive behavioural stress management are two empirically supported ones.”
Tomiyama’s team have also experimented with interventions using classical conditioning – a learning process that occurs when two stimuli are repeatedly paired – to combine the sensation of being relaxed with the experience of eating a piece of fruit. Eventually just eating fruit improved volunteers’ moods.
“That’s a tiny start that will both help stress and let you get some more fruit,” she says. “But there is so much beyond individual control that drives our stressful lives, like poverty, parenting or politics. Those need to be rectified by big, policy-level changes.”
Some necessary interventions might be huge and take years to enact – like addressing income inequality or changing provisions for childcare – but others could be relatively simple, like encouraging more physical activity or providing better information about mental health.
In the meantime, stressing less could be as simple as paying less attention to the unnecessary stressors that force their way into our lives. Try turning off phone notifications, having downtime from social media and staying out of the always-on news cycle.
You can’t eliminate all the stress from your life, but you shouldn’t be dealing with it for most of your day. Even cavemen got to chill out now and again.
De-stress your life
Want to lower your cortisol levels? Just a few simple tweaks can help you to calm (and potentially slim) down.
Use the 3-2-1 tactic :
One meta-analysis of more than 200 studies on mindfulness – the practice of bringing one’s attention fully into the present moment – found that it’s “especially effective” for dealing with stress.
Start with the 3-2-1 exercise. Name three things you can hear, two that you can feel and one that you can smell or taste.
“It’s a simple routine that can help you look beyond your immediate surroundings,” says Dr Danny Penman, author of Deeper Mindfulness: The New Way to Rediscover Calm in a Chaotic World.
Fine-tune your workout :
“Working out in general is a form of stress, as it activates our sympathetic nervous system,” says Mark Bohannon, senior trainer at Ultimate Performance, a personal training company that looks at the hormonal profiles of its clients.
“If people are struggling with chronic stress or cortisol issues, I would recommend removing any long-duration cardio from their routine. Protect your central nervous system from excessive systemic fatigue by stopping a couple of reps short of your limit when weight training.”
Redirect your focus:
Evidence has been mounting for a while that taking a walk in green spaces can improve mental health and reduce stress. But one recent study suggests that, even if you’re in a city, where you direct your attention can have an effect.
Using eye-tracking technology, volunteers who were on a simulated walk to work reported significant improvements in mood and reductions in anxiety when they focused on the greenery around them, compared to those who focused on grey elements.
Remember to breathe:
“One of the simplest things you can do to de-stress every day is to do a short meditation,” says Penman. “You can find some free, guided options online, but simple alternatives can involve pausing for a second to pay attention to your breathing or the feeling of the ground under your feet.”
For a really simple fix, try box breathing: inhale for four seconds, hold for four, exhale for four, hold for four. Do a couple of rounds and activate your body’s parasympathetic nervous system.
Start your day right…
“Having daily practices and progress goals to focus on can be very helpful. Ticking off small wins each day can refocus the mind and provide a distraction from what is causing you stress,” says Bohannon.
“A good example of this could be starting your day by getting morning sunlight for 10 minutes to regulate cortisol levels, stabilise mood and improve sleep quality by reinforcing the body’s internal clock. It doesn’t have to be direct sunlight, so don’t worry if it’s cloudy.”
…And go to bed earlier
Studies suggest that insomnia, as well as other forms of sleep deprivation, can cause your body to secrete excess cortisol during the day – possibly in an effort to stimulate alertness and stay awake.
If you’re struggling to fall asleep or get a good night’s sleep, the mindfulness and meditations mentioned here can help. But also give yourself the best chance of getting some quality shut-eye by avoiding caffeine after 2pm and making your bedroom as dark as possible.
About our experts
Dr A Janet Tomiyama is a professor of psychology at the University of California, Los Angeles. She has been published in JAMA Network Open, Journal of General Internal Medicine and International Journal of Eating Disorders.
Dr Danny Penman is a wellness coach and qualified meditation teacher. He has authored or co-authored books The Art of Breathing: The Secret to Living Mindfully, Mindfulness: An Eight-Week Plan for Finding Peace in a Frantic World, You Are Not Your Pain: Using Mindfulness to Relieve Pain, Reduce Stress, and Restore Well-Being - An Eight-Week Program and Deeper Mindfulness: The New Way to Rediscover Calm in a Chaotic World.
Mark Bohannon is the Chief Experience Officer and a senior personal trainer at Ultimate Performance.
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