When I gave up caffeine, the first day was like a scene out of Trainspotting. Picture a grown man balled up on the couch, sweating in December, on the cusp of vomiting, head split right in two. Then a low-grade headache that lasted for a week set in.
Despite all that, I felt far better overall. I was sleeping sounder and longer. I didn’t have an afternoon slump, and I was less stressed. I didn’t feel as frantic in my work life. Within a few weeks, I’d even lost four pounds.
Caffeine can have many benefits. Research shows that it can boost athletic performance and mental acuity. But there’s a catch to those benefits: They only work if you don’t drink caffeine often.
Your experience with caffeine depends on your biology and how much of it you take in. Before I decided to give it up for good, I was drinking upward of three cups a day. But conversations with people much smarter than myself—biochemists, nutritionists, sleep experts, neurologists—led to me to believe that I was overdoing it at a rate that was bad for my health, sleep, disposition, and performance. Many of us are.
When you’ve been mainlining caffeine for your entire adult life, it can be tricky to parse out how it impacts you. You might be surprised to learn that most people could use an intervention.
How Much Are You Really Taking In?
Ninety percent of American adults ingest caffeine every day, and the average intake is about 300 milligrams, or roughly a medium-size coffee. The humble 16-ounce Starbucks drip coffee contains 310 milligrams. A 20-ounce light roast has 475 milligrams. So if you’re downing multiple cups a day, you could be ingesting north of 1,000 milligrams.
And that can have pernicious effects. Consuming over 400 milligrams a day can bring about problems like headaches, insomnia, an upset stomach, stress, and anxiety, according to the Mayo Clinic. A significant percentage of Americans drink amount or more regularly.
In rare cases, large amounts of caffeine can even increase the likelihood of having ministrokes (also called transient ischemic attacks), during which blood flow to your brain is briefly cut off, says Chris Winter, a neurologist and author of The Sleep Solution. “It’s really weird to see a 21-year-old who’s had lots of subtle vascular strokes over the years, and these tend to be people who were really pounding energy drinks,” says Winter. “There is certainly such a thing as too much caffeine.”
There isn’t a hard number that is unhealthy for everyone, says Maggie Sweeney, a researcher at the Johns Hopkins Medical Institute. Your response is likely influenced by your lifestyle and your genes. Some people can be impacted by less while some have a higher threshold.
When I did the math, I’d been consuming roughly 1,200 milligrams throughout the day and had been every day since 2001. Caffeine has a half-life of roughly six hours, meaning that if you drink 300 milligrams at noon, you will have about 150 milligrams in your system at 6 P.M., about 75 milligrams in your body at midnight, and so on. So my body had likely spent almost two decades under the influence.
Side Effects
I determined I might be overdoing caffeine after talking with Trevor Kashey, a Ph.D. biochemist. He was featured in my bestseller, The Comfort Crisis. He’s currently, in my view, the smartest mind in nutrition.
He has his new clients—who range from average janes to Olympians—go caffeine-free for two weeks as part of a larger approach to suss out foods that might be causing indigestion, sleep issues, stress and anxiety, bloating, or sluggishness. Coffee is a well-known gastrointestinal irritant, Kashey and Sweeney both point out.
Caffeine “works” by blocking the action of adenosine, a chemical that occurs naturally in the brain and clues the body in to fatigue. Meanwhile, it increases the release of cortisol, a hormone that exacerbates the stress response and can interrupt normal patterns of wakefulness and sleep, Sweeney says.
So taking caffeine out of the equation can render two benefits that reduce stress and anxiety. First, it reduces that dump of cortisol, the stress hormone. Second, more sleep makes for a happier, healthier mind and body. Research consistently shows that poor sleep can lead to stress and anxiety.
This is probably why Kashey and Sweeney also frequently hear from clients who say they feel less anxious after cutting their coffee intake. Caffeine has been implicated in anxiety in various strong studies dating back to the late eighties, Sweeney says. The DSM-5, basically the bible for mental-health professionals, officially recognizes caffeine-induced anxiety disorder.
Reducing your stress and anxiety and sleeping more could outweigh any benefits you’d see from caffeine. Stress eating is a major driver of obesity. And Winter explains that better sleep often leads to better eating habits, which was likely why I dropped a few pounds in those early weeks. A 2013 study found that sleep-deprived people ate nearly 600 more calories a day than people who got in a full night’s worth. When you’re tired, the hunger-inducing hormone ghrelin goes up, while the fullness-signaling hormone leptin goes down, Winter says. If you’re eliminating caffeine from sweet coffee drinks or energy drinks, the benefits can be twofold, since you’re cutting a lot of sugar.
How to Give It Up
Kashey has a litmus test to determine if a client is due for a breakup with caffeine. “Ask someone to remove caffeine, and watch the look on their face,” he says. Try this yourself. Do you feel existential dread? That’s probably a sign you might want to reduce your caffeine intake.
Winter echoes the suggestion, explaining that your reaction to the idea of going caffeine-free should offer insight into whether you’re overdoing it. Sweeney relies on well-known signs of withdrawal, like headaches, fatigue, and irritability, to clue clients into their own dependence and decide whether it’s time for a detox.
The good news: quitting doesn’t have to be hell. Sweeney suggests gradually weaning yourself off caffeine. Just start mixing decaf into your caffeinated coffee. “If you’re a particularly heavy user, it may take several weeks to gradually reduce your caffeine consumption,” she says. Drinking plenty of water and herbal tea can ease the transition as well.
Winter described my method—cold turkey—as “unnecessary suffering.” But it felt a lot more practical to me. (Kashey agreed: “Take a shitty weekend with herbal tea and some aspirin,” he says.) I’m glad I ripped off the Band-Aid and didn’t have to do any caffeine-mixing math. Plus, I got to see the results of a caffeine-free diet much more quickly.
Over time, I slowly phased caffeine back into my life. I love the taste of coffee and exploring interesting new roasts. But I was much more judicious with its use. I now drink just one cup a day, and I also avoid it if I know I’ll have a stressful event coming up, like a big public talk. The result: I’m still sleeping better and have learned to let caffeine work for me rather than the other way around.
