On Caffeine

It's a nice but unremarkable story, but now here's the twist: the amount of caffeine involved wasn't large, at least not by American standards. I went from about two cups of coffee a day to about half a cup. I never even felt twitchy physically, only mentally. So, if you're also a moderate coffee drinker, I'd encourage you to try some experiments yourself. You might be pleasantly surprised!

One thing that doesn't work is going cold turkey. I've tried that before, and it's too severe. With no caffeine, I didn't think more clearly, I just felt slow and stupid. It's also unrealistic—there are just too many tasty caffeinated drinks out there. I usually lasted a week or two.

A few years ago, I looked up how much caffeine the various tasty drinks have. The amounts in milligrams weren't memorable, so I converted everything to the “coffee unit”, the amount of caffeine in a normal cup of coffee (150 mg), and made the simple table below, which I've relied on ever since. (I also set all the serving sizes to 12 oz.)

coffee		1
tea		1/2
soda		1/4
decaf		0

Notes:

• The “coffee” line covers both coffees and lattes.
• The number for instant coffee is really 1/2–3/4, but I don't think the difference is worth worrying about.
• The numbers are approximate because they've been rounded. In particular, the number for decaf is not exactly zero.
• The numbers are approximate because there's variation within categories. Different kinds of coffee, tea, and soda have different amounts of caffeine.
• Chocolate contains caffeine, but for normal chocolate the amount is negligible. A dark chocolate candy bar might contain 1/4 coffee unit.
• Coffee contains things other than caffeine. It doesn't matter as far as I know, it's just something to keep in mind.

I'd also like to reiterate what I said about coffee and caffeine in Physical Awareness. Point 15: coffee is acidic. Point 22: caffeine reduces blood flow to the extremities and hence can make you feel cold in winter.