Is drinking coffee bad for you?
Take-aways
Drinking up to 3-4 cups of coffee a day probably improves your health in many ways.
That said, check for contraindications - common ones include pregnancy, severe anxiety, etc.
If you want to avoid the negative effect of caffeine on sleep, depending on how much you take, I’d almost always recommend having your coffee in the first few hours after you wake.
What is coffee? Well, first of all, it’s delicious - that’s what it is.
On a more serious note, there’s a common misconception that all coffee really is is caffeine. In reality, this isn’t true - a cup of coffee has many other active ingredients and nutrients. For example, a cup of coffee can have several grams of dietary fiber and contains antioxidants, which are generally positive for health.
This is all well-and-good, but focusing too much on individual compounds or mechanisms can often lead us astray. How do we actually know coffee isn’t bad for us?
In answering this question, I looked for the biggest review paper on the topic of coffee consumption for health I could find.
So, what’s the deal? Is coffee bad or good for you?
By and large.. coffee is likely good for you.
The largest reductions in risk for many outcomes were generally seen around 3-4 cups a day. These were found for all-cause mortality (Relative Risk = 0.83 compared to no coffee consumption), cardiovascular mortality (RR=0.81), cardiovascular disease (RR=0.85), cancer incidence (RR=0.82). Similar relationships were found for liver disease, metabolic disease (e.g. T2D).
Importantly, a few outcomes showed a negative relationship, and there are likely populations/cases where coffee consumption may not be advisable, such as severe anxiety, cardiac arrhythmias, pregnancy and more.
However.. by and large, coffee consumption seems to be positive for health.
With all the pro-coffee propaganda out of the way, let me give you one warning. Caffeine consumption can meaningfully impact your sleep, reducing your total sleep duration by close to an hour, making it harder to fall asleep and more.
In fact, a recent meta-regression by Gardiner and colleagues found that, to avoid any negative effects of 200mg of caffeine consumption on sleep, you’d likely need to consume it at least 12-13 hours before going to bed. Any later than this cut-off time and you’d start seeing a negative impact.
Cut-off times to mitigate impact of caffeine consumption on sleep at various doses, assuming you go to sleep at 10PM.
Why?
As I mentioned in the introduction, coffee has many more compounds than commonly assumed, many of which are likely beneficial. Importantly, some research suggests that filtered coffee is generally more health-promoting than unfiltered coffee, so certain methods of consuming coffee may be superior to others.
