I’m a big believer in intermittent fasting, and usually don’t eat my first meal of the day until 1:00 or 2:00pm.

I do, however, drink coffee most mornings. And recently, especially if I’m feeling hungry, I’ve been test-driving ’Bulletproof Coffee.’ Dreamed up by body-hacker Dave Asprey, it’s a recipe that’s since become a ’thing’ in both the Silicon Valley and sports performance worlds. In theory, at least, it’s meant to boost metabolism and mental performance, and to make people feel full without spiking insulin.

Here’s what goes into it:

1. 1cup Coffee. Freshly-roasted, freshly-ground coffee has higher anti-oxidant content, so buy beans regularly, and grind them yourself. (Asprey himself sells a coffee bean that supposedly has lower mold content, though the science backing the danger of mold in coffee seems weak at best.) If you’re like me, and way too lazy for that, buy a Nespresso machine instead. It makes great coffee (they’re in use by 30% of the Michelin-starred restaurants in the world!), and uses vacuum-packed capsules that keep the coffee grinds exceedingly fresh (enough so to even counter the mold/mycotoxin concern, if it turns out to hold water). I use two Fortissio Lungo capsules, each brewed as 110ml lungo pulls, which yields a delicious 8oz cup.
2. 1tbs Butter. As Michael Pollan noted, you aren’t just what you eat; you’re also what you eat eats. Grass-fed butter turns out to be waaaay healthier than grain-fed butter, and you can buy Kerrygold all over the country (in places like Costco, Trader Joe’s and Whole Foods). While grass-fed butter is loaded with nutrients, it’s the butyrate in particular, a fuel that’s particularly good at powering your brain, that gives you a mental boost.
3. 1tbs Coconut Oil. For bonus points, you can swap the coconut oil for medium-chain triglyceride oil, which contains the portion of the coconut oil that has the most beneficial effects. I like this brand, which is extremely high-quality yet reasonably priced, and comes in a container large enough to last several months.

Here’s how you make it:

1. Put all three into a blender. As I’m way too cheap for a Vitamix, (especially as I mostly just blend protein shakes or bulletproof coffee), I’ve used an earlier version of this sucker for several years with excellent results.
2. Blend! Should only take a couple seconds. You’re set when there’s a thick froth on top, like the foam on top of a latte.
3. (Add Cinnamon?) This one’s an optional bonus step, which I only started recently based on some of cinnamon’s clear health benefits. Also, it tastes awesome.
4. Drink. Then feel excellent – both physically and mentally – for hours to come.

At least, that’s the theory. Thus far, I seem to be liking it. But I’ll be tracking performance and biomarkers going forward to see the impact longer-term.

And, either way, a very important warning: WHEN YOU FIRST START DRINKING BULLETPROOF COFFEE, START WITH ONLY A TEASPOON EACH OF BUTTER AND OIL, AND BUILD UP SLOWLY. It can be a bit of a shock to you digestive tract, and you want to give your body a week or so to get used to things as you build up to full strength.

Relatedly, a brief cautionary tale:

About a year ago, I was at a fitness event. A booth there was selling Bulletproof Coffee, and they were bringing freshly-blended cups for free to the VIP area, where I happened to be with a friend.

When we first arrived, we both grabbed a cup to try. Then we headed our separate ways. A few hours later, I ran into him again, and the cup was still in his hand.

“You’re still nursing that Bulletproof Coffee?” I asked him.

“Oh no,” he replied. “This one’s my fifth!”

We headed into some meetings together. And then, after about thirty minutes, he excused himself to use the bathroom. I didn’t see him again for the balance of the afternoon.

So, enjoy the Bulletproof. But ease your way in. With great power comes great responsibility.