Counting, and the cut-off

The first practical step is to know the number and to set the time. Everything in this chapter is my own method, built on the research earlier in the book.

Add up the week. Take the notes from chapter 1 and price each item with the NHS figures. A hundred for a mug of instant, more for filter or coffee-shop, seventy-five for tea, forty for a can of cola, eighty for a small energy drink, and a bit for dark chocolate. Get a daily total for each day and an average. This is the size of the habit. Most people are surprised, and the surprise is useful, because it makes the afternoon cups visible as caffeine rather than as coffee.

Find your last dose. For each day, note the time of the last caffeine of any kind. Compare it with your bedtime. Six hours is the line the evidence supports, and I'd treat it as the minimum. If your last dose is inside that window on most days, that's the first thing to change, and it's the change that pays soonest.

Set the cut-off. Pick a time after which you have no caffeine at all. Not a target to aim at, a line. For an eleven o'clock bedtime, six hours gives five o'clock, and I'd go earlier, because the evidence in chapter 7 was for a fixed dose and your afternoon may have more than one. Two o'clock is a good line for most people. After it, decaf, herbal tea, or water. Tea counts. Cola counts.

Move the cut-off first, before anything else. Don't reduce the morning cups yet. Just move the last dose back to before the line. This is the smallest change with the largest effect on the night, and it costs you nothing in the morning, where the pick-up feels most needed. Do it for a week and watch the morning score.

Keep the notes going. Time of each dose, time you fell asleep, morning score out of ten. The score is your evidence. In my experience of people who do this, the morning score starts to move within the first week of the cut-off alone, before any reduction in the total, and that's the moment the habit stops looking like a fact of your nature and starts looking like a schedule.

Two cautions. If moving the cut-off leaves you with a big afternoon shortfall, because a lot of your caffeine was in the afternoon, you'll feel it for a few days, and chapter 19 is about that. And if you're one of the people the preface described, with pregnancy, a heart condition, or a medicine that interacts, the limits you've been given come first.