How to Survive a 40-Hour Fast

Coffee. Lots of coffee.

That might be my big, bold secret to skipping food: load up on caffeine, a proven appetite suppressant and pretty convenient opportunity to feel like one of those Mac-toting hipster kids at the local cafe.

The trick to surviving any lengthy fast, though, might require a little more verbiage. I’ve done daily Intermittent Fasting for over six months, now, and grown more comfortable with it all the while, to the point where forgoing food for the entire train ride from Los Angeles to Portland seemed easy as can be.

For the DIF newcomer, though? Skipping a single meal — let alone two, let alone five! — might seem daunting. This guide, then, is intended to aid every one of you in your experiments with fasting, with a small slant towards the lifestyle scientists aiming for a day or longer without sustenance.

1. Decide you’re going to do it. Really decide.

The mental component, surprisingly, might be the best trick of all.

Johnny Nguyen, my go-to intermittent fasting guru, calls it turning off the valve — a decision, as I understand it, to ‘turn off’ your eating for any given period of time. You decide in advance that you aren’t going to eat, and then (presumably!) have an iron-clad will even when your stomach eventually starts mumbling and grumbling.

That sounds a little new-agey, I’ll admit, but I’ll counter with my own experience: it works. It works spectacularly well, in fact, adding a hefty amount of weight to the “mind over body” concept we usually experience in response to pain or stress. It’s interesting to note too that my hunger levels actually drop whenever I turn off the valve, the result of which made my last long fast the easiest I’ve ever encountered — despite being the longest yet.

Turn off the valve. Decide, before you enter the fasting window, that you’re not going to eat, and make a promise to yourself to stop obsessing over food until you want to eat.

2. Start drinking!

But stick to a few select choices: coffee, tea, and water, all of which are zero-calorie (or very nearly) while still providing the sensation of being full. Coffee in particular satiates me well until the evening hours, making a cup of joe right around noon an easy substitute for lunch (and an excellent buildup to a much larger meal for dinner).

Drink something. Water with a few squeezes of lemon juice is another popular option, but the point remains the same: whenever the hunger starts creeping in, have a glass of water and wait five to ten minutes for the pangs to settle. You might be surprised to hear that they nearly always do.

3. Get out of the kitchen!

In all sincerity, folks, get away from food. There’s little reason to make this any harder on yourself, and it just so happens that the average faster will find herself surrounded by friends, family, etc. during the conveniently scheduled times each day where they stuff their faces with pizza and pasta.

Want to feel hungry? Sit next to your fellow workers during lunch and make bedroom eyes at their meals. Want to remind yourself that the modern person’s hunger cues are horribly out of sync with their actual need for sustenance? See step #2.

4. Get busy!

Another common sense suggestion, I guess, but one that bears mention: distract yourself. Skipping meals on a lengthy train ride was made much easier by all the writing I did instead, though the trick isn’t limited to transportation alone. Watch a movie. Read a book. Play a game. Devote yourself to a project for however many hours you like, focusing so intently that you forget to eat — albeit somewhat deliberately.

Don’t sit around and stare at the refrigerator. You’ll be tempted to when you first start fasting, but it’s far easier on both body and mind to use your fasting period in the name of productivity instead.

5. Eat wisely the night before the fast.

The latest article on Leangains outed an interesting study: Greater Weight Loss and Hormonal Changes After 6 Months Diet With Carbohydrates Eaten Mostly at Dinner. For the sake of simplicity, let’s say the study was designed to observe the impact of eating a carbohydrate-rich meal before sleep, the results of which are completely spoiled by the title.

It’s a fascinating piece of work, in any case, that suggests eating most of your carbs — potatoes, rice, fruit, etc. — during the evening has more benefits than expected. Increased weight loss and a larger reduction in body fat are two of them, but the most interesting benefit for fasting came in the form of reduced “hunger scores” — in other words, reduced hunger during the daylight hours.

Don’t take this as an invitation to stuff your face with excess calories before bed, of course, but keep these results in mind the next time you’re planning a fast. Everyone responds to carbs differently, too, but you might find your next-day fasting goes a lot smoother if you concentrate most of your carb intake in the last meal before sleep.

Wrapping Up

You’ll notice a common theme here: insomuch as fasting can be considered a rigorous physical challenge, your success is often best determined by your mental approach. The next time you attempt a long fast, then, keep these few blurbs in mind:

1. It’s healthy to skip meals.

2. It’s okay to feel hunger.

There’s an undeniable stigma against skipping meals in modern culture, and fears of the so-called “starvation mode” are too often thrown around without actually knowing what that means. I’ll be tackling that issue and more with the impending relaunch of Three New Leaves, so keep an eye on this space — and why not grab a copy of my upcoming book, Roots, which covers it all in full?

Thanks so much for reading!

If you like what’s going on around here, then why not have free updates sent directly to your inbox or to your RSS reader?

If you want to spread the good word about this post, however, please consider one of the following:

  • Click the retweet or stumble button down below!
  • Like this post on Facebook and share it with your friends!
  • And hey! Did you know that Three New Leaves has an official Facebook page? Do me a favor and like that too!

It all helps, in any case, to share these ideas. I really appreciate it! And you can follow me on Twitter, too. That always makes me smile. :)


  1. Nina Yau says:

    Yay for coffee!! Couldn’t agree more. Cheers to that!

  2. Trey says:

    40 hours sounds intense. I’ve done 24 hours before and I’ve had some great results with IF, but I would really have to psych myself up for that long.

    Good advice though. I tell people about it and they think I’m starving myself. I look at most people though and think more people could stand a little more “starving”.

  3. Nina Nelson says:

    The first suggestion is definitely the most important. It’s ridiculous how many things I’m able to do now just because I decide to do it. If only I had realized that before. Thanks for the tips Matt!

  4. Davorin says:

    I’m on my first 40 hour, 14 hours in, and I feel strong like an animal. I can’t wait to wake up tomorrow and taste the sweet juice of the 36+ hour tail end.

    • Matt Madeiro says:

      Keep rocking it, Davorin. :) I felt so strong at the end of my first 40 — powerful and focused. Enjoy!

  5. Meghan says:

    Tomorrow August 22,2012 I’m going to do my second 40 hour fast I’m nervous but excited at the same time. Going for Wednesday night to Friday morning. It will be intresting. Glad to give my body a break from eating all the time and filling it with food