Listen to your body. It's the kind of comment that turns a lot of people off, that makes them think of what Boris Johnson would call "uncooperative crusties with their hemp-smelling bivouacs." Bivouac, anyone? I just looked it up. It's a temporary shelter, like a tent encampment, to you and me. Though, I should say, not according to urban dictionary.
I never used to drink coffee. I didn't like the taste, the smell or indeed the charming stench that emitted from people's mouths after they'd enjoyed it. And I'm also quite bad at just sitting around. But then coffee shops arrived, pedalling their coffee nectar. And my children arrived, pedalling their 5am get-up times. And yet still I resisted the urge. And then two years ago, it all became too much, and I gave in, and started paying £2.70 for a flat white so beautifully made I could no longer object to paying £2.70.
Like any addiction, it started slowly. A cup a week. Then a cup a week plus one if I'd had a bit too much to drink the night before. Then a couple of cups a week plus the odd extra. And then before I knew it, it was every day. And then every day, plus 2 one day if I'd had a bit to drink.
And in some ways, maybe that doesn't matter. Except for the slightly horrifying £18.90 going to Costa per week. Though, in fairness, that little feather of milk does look soooooo pretty.
But here's the problem. I started feeling run down all the time. And needing more coffee. And the reason why? Because instead of thinking "I'm tired - I need to go to bed earlier" earlier in the day I'd thought "I'm tired - I need a coffee" and then even when I wanted to go to bed, I couldn't necessarily sleep. The sleep thing was a minor distraction - I appreciate in most people's worlds, what I was having was not a lot of coffee. But I had stopped listening to my body. And much as you might hate that phrase, it was causing me harm. I was causing me harm.
Some facts. A Costa flat white contains 277mg of caffeine. Diet Coke - another vice of mine - contains 42mg of caffeine per 330ml can. Coke Zero has 32mg per 330ml can. A cup of green tea is much the same caffeine-wise as a can of Diet Coke. Coke is a bit less. Regular tea is 50mg a mug. Instant coffee is about 100mg, filter 140mg. Advice from the NHS in line with about a billion studies assumes that 400mg per day for a healthy adult is fine. It's 300mg if you're pregnant. And 2.5mg per kg of weight if you're 3-19. Feeding your 2 year old coffee? Then you have it much, much too easy with sleep.
But how much harm was I actually doing? Latest word from the NHS came after a systematic review carried out in the States. For those of you unfamiliar with this, this is where a review is made of data gathered from previous studies, so it's worthwhile, but not without its flaws. There are issues too with any food or drink study (and there were over 350 studies they reviewed). Participants in studies are bad at self-reporting, and often unintentionally get it wrong, before you've even got to the complications of participants deliberately misrepresenting figures. And as always, it's really really really important we separate correlation and causation. This can get complicated fast. For example: Does coffee make you anxious? Or do anxious people drink more coffee? Does being an *sshole make me more likely to buy cocaine? Am I an *sshole when I take cocaine? Or was I an *sshole before I took it, and you've only just noticed?
The review of studies basically corroborated what everyone thought before, which suggested that the amounts mentioned above will do you no long term harm, though that requires you to think long term harm is only harm if it's to your bone health, reproductive health, heart health or what they helpfully call "behaviour", yet will cause you harm if you think headaches, high blood pressure and increased anxiety are also harm.
So was I doing myself major harm? No. I was at the upper limit they don't desperately want you to exceed, and I was generally short of it or dancing around it. A little bit of heart racing here. A little bit of high blood pressure there. All a fair sacrifice in return for me not banging on to everyone I met about how tired I was. And as for the feeling run down and a bit tired too often? The authors of the report discuss that caffeine is so unbelievably good at what it's meant to be good at - blocking sleep - that, essentially, if you don't know it might mess with your sleep, you're a proper f*cking idiot. I mean, those aren't the words they use. They're mine, directed at me. And I get why they say that. But sometimes we need prodded to remember what should be obvious.
Do I get tired a little earlier? Yes, probably. And then I go to sleep. Do I still have the odd coffee? Absolutely, and it sees me through when I need it to. But I'm fully aware again of what's it doing for me, the good and the bad. But do I feel better? Yes. Yes. Yes. Yes. Yes. Yes. I feel better in the mornings, better in the afternoons, better at night. I feel so good I could bivouac myself silly.
*A side-note on decaf (which still has some but a very small, sub-Diet Coke volume of caffeine): it has all the benefits of coffee - all the antioxidants that are so great for us - with none of the heart-racing, anxiety-inducing, sleep-blocking effects. BUT it maybe increases your LDL cholesterol, and for those of you who remember that there's good and bad cholesterol (excellent - one house point for Gryffindor), I'm going to be the one to break it to you that LDL is the bad one. So pick your poison...