How Reverse Intermittent Fasting May Affect Your Circadian Rhythm

As an author and as someone who likes to dive deep into research, I find there's an especially productive writing time that happens very late at night. It's quiet. It's a time when I can focus. And since nobody else in my home is awake then, it's a great period of alone time. As much as I enjoy those late hours, they come at a cost.

In the morning, I still have to take the kids to school at the usual hour. Staying up until 2 a.m. and waking five hours later, over and over, wears me down. It would wear anyone down. After a while, that kind of schedule makes you feel like garbage in the morning, and you wonder whether the exhilaration of the late-night creative burst is really worth it.

In order to hack sleep, you have to hack billion-year-old evolutionary mechanisms, ones that predate the origin of animals—even the origin of sleep itself.

I'm talking about back when the most complex form of life on Earth was single-cell bacteria floating in the ocean. Peak nutrients were available at noon, when the sun was highest. The sun would come up, and those ancestral bacteria would float up from the cold depths of the ocean. They would reach the surface and get their first jolt of morning sunlight, which would be a reddish color—because, hey, that's what sunrise looks like when you're floating in a primordial ocean. And then they would start getting energy from the sun and begin feasting on whatever was in the water around them.

That whole legacy still lives on inside of you. The daily cycle of light and nutrition is encoded into your cells, and it's persisted for eons because it's kept us in sync with our planet. By selectively going without—without food, artificial light, or electronic distractions—you can restore harmony with your ancient internal rhythm.

You're going to combine the timing of food and sleep to trick your brain into moving your sleep window. Think about the stimuli that affect your body clock. The first is light, including its color, intensity, and angle. The second is calories, or rather calories consumed.

If you believe you'll starve without three meals a day, your sleep window will remain frustratingly out of your control. There aren't yet any ironclad studies to back up my theory, but I estimate that light controls about 70% of the strength of your circadian rhythm, food about 20%, and room temperature is probably the other 10%.

This formula worked astoundingly well for me. For the past 14 years, I reliably went to sleep at around 2 to 4 a.m. Using the above techniques, I now get tired and go to sleep at 11 p.m. and am able to wake up without an alarm clock seven hours later.