Why it might be time to give up caffeine: From eye-twitches to insomnia and anxiety, what it REALLY does to you - and the truth about decaf

The US Brewers Cup Championship is the ultimate event for coffee nerds, complete with 37 pages of rules governing everything from liquid volume to alkalinity. The judges are purists who might pale at the idea of Nescafé, yet this year’s prize went to a brewer who served – brace yourself – decaf.

Historically, decaffeinated coffee has not been celebrated. To some it’s flavourless – to others, pointless. Yet the beans used by winning barista Weihong Zhang were unapologetically buzz-free, and sophisticated enough for any connoisseur – they boasted notes of eucalyptus and strawberry.

The brew’s triumph indicated a larger trend: decaf is hot. The global market is expected to increase from £15.3 billion in 2022 to £22.5 billion by the end of the decade.

Advances in technology appear to be behind the boom. A quick explainer: coffee beans are seeds found in the ‘cherries’ of coffee trees. The green seeds are sent to roasters who turn them into the brown ‘beans’ we’re familiar with. In the case of decaf, they’re first treated to remove the caffeine.

With cheaper decafs, this is often done with methylene chloride, which has become controversial, as it’s a carcinogen. Some critics argue it should be banned; defenders say that there are such tiny amounts in a decaf that any threat is negligible. Still, consumers increasingly prefer their decaf flat white to be made ‘naturally’ – using water, carbon dioxide or ethyl acetate from sugar cane.

More attention is being paid to crops, too. ‘Producers used to take bad beans they couldn’t sell anywhere else and say, “OK, we’ll use them for decaf”,’ says Howard Gill, head roaster at London sustainable coffee brand Grind. ‘Today, farms deliberately grow beans with a flavour profile, size and consistency that makes them great for decaf.’

Moreover, two coffee drinkers in five want to reduce their caffeine intake, according to market-intelligence agency Mintel. ‘At Grind, decaf sales are growing fast,’ says Gill. So, should you switch? Let’s sort fact from fiction.

‘Caffeine is bad for you’

That depends. ‘People often say, “I’m trying to be good and cut back on coffee”, but drinking coffee is not problematic for those who tolerate the caffeine,’ says Dr Federica Amati, head nutritionist at health-science company Zoe and author of Every Body Should Know This (Michael Joseph, £22). ‘We’re all different in how we metabolise it, and some people are genetically more susceptible to negative effects. You have to respond to your body.’

Many people drink three to five coffees a day without any problem, while others experience anxiety, insomnia, an increased heart rate and even eye-twitching. A few get these symptoms after just one cup. This may evolve over a lifetime.

Perimenopause causes some women to suffer anxiety and sleep disturbance even without caffeine. ‘At that time, you might find that the cup of coffee you previously enjoyed in the morning now makes you feel more anxious,’ says Amati.

Psychiatrist Dr Alex Curmi was concerned about his caffeine habit of two to six shots of espresso a day: ‘As the second cup of the day faded out, I would get a visceral feeling of anxiety.’ He decided to give up for six weeks and documented the experiment on an episode of The Thinking Mind Podcast.

He found the withdrawal symptoms manageable and felt calmer. ‘For the first few days, I could tell there was a slump in my performance – I would say I was at 80 per cent – but I also felt a sense of relaxation.’

After six weeks, he reintroduced caffeine: ‘The first coffee I had after that break felt insane. I felt I could learn a language and write a book with that intense burst of energy,’ he says. Curmi now feels that one cup a day is enough to enjoy the benefits.

In pregnancy, there is evidence that more than 200mg of caffeine a day (two mugs of instant coffee) raises the risk of miscarriage and may restrict a baby’s growth. Sufferers of irritable bowel syndrome may find that caffeine irritates their gut. Other conditions can respond well to its stimulant effect: some people with Parkinson’s disease report that caffeine helps them move more freely, and some with ADHD find it helps them to focus.

‘Decaf is bad for you’ 

Not true. Coffee’s health benefits are significant, with or without the caffeine.

‘They include improved cognitive function and reduction in the risk of heart disease, colon cancer and death from any disease,’ says Amati. ‘Coffee is high in polyphenols, and it contains fibre, and together they act as a brilliant prebiotic mix for the gut microbiome.’

Back to menopause: it’s very important at this time to look after your gut. ‘A subset of bacteria in the microbiome is sensitive to oestrogen and starts dying off in menopause,’ Amati says. ‘So if caffeine bothers you, rather than giving up coffee you could switch to decaf. You still get the polyphenols and fibre.’

Most coffees – even decaf and instant varieties – don’t contain weird additives, but ready-mixed sachets marketed as ‘cappuccino’, for example, may contain emulsifiers. ‘And try to avoid sugary coffee,’ adds Amati, ‘because then some of the positive outcomes are counteracted.’

‘Decaf tastes inferior’ 

No. Experts swear this is no longer the case. ‘Roasters pay a lot more attention to decaf now,’ says Gill. ‘Traditionally, as the beans weren’t good quality, it would be roasted super-dark – the equivalent of serving a steak well-done – to drown out negative flavours. Now roasters make decaf coffees a lot lighter to highlight the good characteristics.’

‘I need caffeine to wake up’

Maybe. ‘Studies show a low to moderate dose of caffeine – up to three cups a day – gives us increased alertness, energy and ability to concentrate,’ says Amati. ‘And if you have caffeine before exercising, you tend to have more effective workouts.’

However, some heavy coffee drinkers report withdrawal symptoms, such as grogginess or headaches, first thing in the morning; there’s also evidence that as your body gets used to caffeine you lose some of the perkiness you first enjoyed. 

‘If you drink lots of coffee, yes, there will be receptor changes in your brain,’ says Amati. ‘But that doesn’t mean it stops having any impact on alertness at all.’ ‘Most drugs are a deal with the devil as you get a bit more upfront and you pay for it with a deficit later, and that includes caffeine,’ says Curmi. ‘I like a bit of extra energy in the morning, and if that means there’s a slump afterwards then I’m willing to pay that price.’

‘Decaf isn’t caffeine-free’

Correct. But it contains very little. If a cup of normal coffee has between 80mg and 100mg of caffeine, a decaf will contain between 2mg and 15mg. In the UK we follow European law, which states that green decaffeinated beans should contain no more than 0.1 per cent caffeine, and decaf instant no more than 0.3 per cent.

‘I’d lose my morning ritual’

Not so. Decaf coffee is available in all the same forms as caffeinated and will still smell delicious as you brew your morning cup. Erin Reed, director of marketing at decaffeination company Swiss Water, argues that the process is even more meaningful. ‘We always say decaf drinkers are the true lovers of coffee,’ she says, ‘because they’re not in it for the functional caffeine – they’re in it for the taste and the experience.’