Fasting: a Fast Way to Greater Badassity?

Despite the fact that I am Mr. Money Mustache, I now realize I have led quite a wimpy and pampered life when it comes to the area of food.

As a young child, I was reportedly one of the pickiest eaters in history, refusing to try anything that wasn’t prepared at home, in exactly the way I was used to it. By the time I was a teenager, I had become an enthusiastic omnivore, but arbitrarily decided that low-fat diets were most healthy. Following in the footsteps of the heroic bodybuilders in the pages of the “Flex” and “Muscle and Fitness” magazines of the early ’90s, I ate six small meals a day, stopping for a sandwich between each of my classes in high school. Even now, I generally have a nicely stocked fridge and am deprived of nothing. In short, I’m a wimp.

Writing this blog has opened up my eyes to other ways of doing things. I’ve heard from people who eat only one large meal per day, as well as people who regularly and comfortably go without food for one or more days. And here I am, never having gone more than about 12 hours without food, for almost 38 years running now.

After switching to a much-lower-carbohydrate diet, I’ve noticed a considerably longer period in my natural eating cycle. Like a car with a giant gas tank, I can now go out on a long day’s adventure without having to plan out a bunch of little snacks to keep me going. This has led me to want more: I’ve been planning to try out an experimental fast on myself for some time now. Far from being an unhealthy fad experiment, everything I’ve read suggests that going without food occasionally is actually extremely good for you. So I am just about ready to press the button.

The goal is mainly to understand more about self discipline, as well as learning new things about how the mind and the body work together. Fasting will be just another example of a healthy self-deprivation – the kind we must all do in all areas of life to remind ourselves just how cushy our normal life is.

But while I was waffling about all of this beginner fasting stuff, a friend of mine went and busted out a 3.5-day fast with no preparation at all, making me look even wimpier.

Enough of this crap, I’m starting a little 24-hour fast myself RIGHT NOW. So as you’re reading this, I’m probably right in the middle of it.

What follows are my friend’s notes from the experience.


The Fast
(by MMM reader HirsutePirsute) 

I was fascinated by an article I read this spring in the March 2012 issue of Harper’s Magazine by Steve Hendricks: “Starving Your Way to Vigor: The benefits of an empty stomach.” It was well-written and informative and made a good case for occasional or targeted fasting as a way to better health. The author ended up doing a weeks-long fast, far short of some of the longest fasts, but still longer than mine, detailed below:

Monday, August 20

9PM – Tonight I embark on what I hope will be a three day fast. Not highly impressive compared to the great fasts, but a challenge for me nonetheless. I gorged myself on roasted veggies, burgers, ice cream, cookies, and chocolate milk in anticipation of the fast. I imagine I will weigh close to 175 tomorrow morning. Hopefully that will be closer to 167 when I next eat on Friday morning.

Tuesday, August 21

AM Weight: 173 lbs

10:23AM – I’ve had my first few pangs of hunger. I find myself absentmindedly thinking I can just grab a bite of something whenever I want.

5:25PM – I enjoyed a bit of an alcoholic buzz feeling for most of the afternoon. I still have that feeling, but I’m hungrier – I almost stuck a piece of cheese in my mouth without thinking while making tacos for the kids.

A recent study done at Stanford found that cancer tumors shrank when the subjects (mice with human tumors implanted) were given an antibody that masks a protein (CD47) that normally protects cancer cells from macrophages. A study at USC found that fasting causes cancer cells to reduce the expression of protective genes, making them more likely to die. Fasting also allows chemotherapy to target cancer cells with less adverse effects on normal cells. Maybe a combination of these treatments can radically reduce cancer’s effects.

10:25PM – Anxiety is magnified when one has low blood sugar (LBS). My stress level was pretty high tonight after an unpleasant email exchange. I don’t know how much of this stress was due to a lack of food and how much was real, but it was comforting to think that it was mostly the former. I was especially hungry at dinner time. Like a bad TV show, everything I watched seemed to show people eating food. I’m looking forward to a giant pepperoni pizza in a couple days. Guess I’m being pretty wimpy, really – I’ve made it one day.

Wednesday, August 22

AM Weight: 170 lbs

7:52AM – My dreams last night were more vivid than usual. I wonder if this means I slept lightly, but I feel rested. And I don’t feel hungry, kind of a typical morning.

PM Weight: 167 lbs

4:08PM – I spent the morning working on a deck and much of the afternoon working in the shop. It was moderate activity, and for the most part I didn’t think about food. As dinner time approaches (and activities dwindle) I’m thinking more about food, but I’m less hungry than yesterday at this time. I have a similar level of energy and buzzedness as I do when I normally experience LBS (which sometimes occurs if I have a light lunch and wait too long before dinner).

Thursday, August 23

AM Weight: 168 lbs

7:53AM – As I was going to bed last night I tried to envision foods I would enjoy. I wasn’t extremely hungry, but I did experience some Pavlovian drooling. The pepperoni pizza was still foremost in my mind, and a bologna sandwich sounded good. Meat/carb combos were much more droolworthy than veggies, fruit, or even meat alone (although greasy, drippy things like bacon, wings, or ribs were appealing). I slept less well, waking up often, and had a slight headache. This morning I feel a little groggy, sleepy, low energy, maybe a bit sick, and I have a short fuse with the kids.

12:35PM – I messed up. My son and I were visiting a house we rent out and I asked him to pick a pear from the pear tree. I took a couple bites from the pear before realizing I was in the middle of a fast. I wasn’t even hungry, it just comes naturally to grab a bite whenever and wherever you are. It was a fucking delicious pear. I’m going to forgive myself that transgression, though – it wasn’t much more in the way of nutrients than the toothpaste I accidentally ingest. There was something biblical about my sin, though the apple was a pear and the snake was a worm in said pear (a tiny slice of protein?).

8:53PM – In the afternoon I drove to Boulder. I was cognizant of my potentially reduced driving ability, but I did fine. Back home I thought I would rest and read and watch TV for the evening, but I got a text from MMM himself asking if I wanted to go pick apples from the neighbor’s tree. So there I was 15 feet up in an apple tree, picking apples and sawing off broken limbs with an extendable chainsaw. I really wanted to eat an apple, but I was able to avoid that sin. MMM had mentioned that he’d heard that foraging tends to dispel feelings of hunger so one can focus on the task at hand – that seemed to bear out. Back home I made dinner for the kids (which I’ve done all three nights of the fast) – everything was looking tasty, even the compost slated to go outside. If only the kids knew, maybe they’d actually eat the food I make them.

You know when you really have to go to the bathroom and there’s a bathroom nearby, your body anticipates the proximity of said bathroom, and gets ready to release? Well, it’s a little bit like that for me right now, knowing that I’ll soon be mowing down some food, but working hard not to release too early.

I’m feeling good, not too hungry but still excited to eat tomorrow. Not surprisingly, no movement of the old bowels has occurred since yesterday morning. Piss, on the other hand (comma placement was important there), has been more forthcoming, and has retained its normal golden hue. I’ve been drinking a lot of water.

Friday, August 24

AM Weight: 164 lbs

7:49AM – Not a great sleep again, but I’m feeling better than I did yesterday morning. Some cottonmouth, a mild headache: indicators of dehydration, I guess. My stomach growls at me occasionally, but I’m not hungry, so I’ll wait until I am to eat.

11:11AM – After 3 1/2 days, the fast is done. I just imbibed 24 ounces of delicious kale shake – made with kale from my garden, a couple pears from my pear tree, a couple apples from the neighbor’s apple tree, some organic strawberries, a splash of organic apple juice, a dash of cinnamon, and some ice blended together. Although I still wasn’t feeling particularly hungry, it was the best kale shake I’ve had (but I’m inclined to believe that’s because it was the best kale shake I’ve made). Now it’s suffusing throughout my body, turning me superhuman (and it will likely be suffusing its way out of my body in short order, hopefully not too rapidly). Oh, and that pizza is still on the docket.

Afterword – One thing that occurred to me while fasting is that there are millions in the world who aren’t eating right now because they don’t have enough food. My little three day fast was luxurious and cushy by comparison, knowing that I would soon be eating again. There is enough food on the planet to feed everyone, yet we have environmental and distribution problems (many of them willful yet easily avoidable). A growing population and changing climate will exacerbate those problems and stretch our food supply further. First-worlders (especially Americans) need to learn how to do with less, waste less, and cooperate more with the rest of the world to help curb the growing catastrophe.

Disclaimer: Please consult a doctor before you do any extended fasting – neither MMM or HirsutePirsute wants anybody dying because of stuff they read here!

Further Reading: Years later, a reader shared an interesting article suggesting that fasting may affect female fertility.  On the other hand, other women swear by the practice and see benefits. The deciding factor might be the intensity of the fast. Some readers on the forum have experimented and shared their results here.

  • Dave August 24, 2012, 8:22 pm

    Actually, considerable new scientific evidence shows that fasting may have dramatic positive effects on your body by forcing it to go into a “rest and repair” mode. Fasting induces lower levels of Insulin like growth factor, and you don’t necessarily need to completely fast, even calorie restriction on alternate days can have very positive health effects. Here is a BBC documentary on the topic aired about 2 weeks ago, kindly uploaded to youtube:


    Makes sense, as our evolutionary ancestors fasted regularly, though not by choice, rather by spotty availability. We live in a modern society that has insane amounts of calories, always ready to be consumed. Presenter is also a MD himself.

    • Chad August 25, 2012, 4:56 pm

      Wow that video was so fascinating!!! I’ve never seen anywhere else before where too much protein could be bad. MMM’s post was mildly interesting for me until I watched this video. Now I can’t stop thinking about this subject.

      Oh and 19 hours since my last meal :)

  • Richard Van Manen August 24, 2012, 8:23 pm

    Its been awhile since I’ve done a fast, but drinking lots of water definitely helps. Keeps you feeling full. Staying active is important too, anything to keep the mind from concentrating on food :)

    • Nurse Frugal August 26, 2012, 10:20 pm

      I’ve done a fast before, it’s incredible how long your body can go without food, especially when there is a specific reason for your fasting. It also makes you have a new appreciation of food.

      This reminds me of an incredible non-profit group called Nuru International. This group’s mission is to end extreme poverty in remote, rural areas and teaches locals how to harvest and sell their own food. They can be found at http://www.nuruinternational.org/ They are helping people who struggle with non-purposeful fasting on a regular basis; they simply don’t have enough money to eat.

      • FreeUrChains August 29, 2012, 10:07 am

        I think i will stick with eating healthy and light, and exercising an hour a day to lose 2lbs of fat per week for a year straight.

        Much simpler, though just as challenging if you can’t spare the time.

  • lecodecivil August 24, 2012, 8:36 pm

    When I was in middle and high school I attended a summer camp that taught primitive living and skills in the mountains of NC. One of the activities was a two-day fast. The first day everybody went their separate ways into the woods, and the second day we came back together into small groups to build sweat lodges, and finished the second day in a lodge. It was a great way to build focus and discipline – when you’re sitting out in the woods waiting, you don’t have much to focus on but being hungry so you learn to just put it to the back of your mind. It is an excellent skill for building badassity, but be extremely careful when deciding to undertake a fast and as MMM says, consult a doctor first.

  • Dragline August 24, 2012, 8:37 pm

    I was about to upload that video myself — it summarizes how medical science is catching up with conventional wisdom. But don’t be a wimp — go for 3 days. You don’t get the true benefits until about then, after you go ketogenic and the hunger pains and light-headedness stop completely. You’ll feel weirdly energetic and if you have any pain in your joints, it will go away. Trust me. Your body essentially starts eating all the useless crap laying around. Drink lots of water and have some bouillon if you really need something.

    This is an ancient practice that was very popular in many ages. You have got to go to pre-antibiotic literature to understand or appreciate it. Read some of the works of Bernarr MacFadden to understand what was known then: http://www.bernarrmacfadden.com/freebooks.html

    • Mr. Money Mustache August 24, 2012, 9:18 pm

      WOW! Thanks guys, and again I am amazed at the concentrated badassity coming out of the woodwork around here. You could never post on a mainstream site about such a serious voluntary deprivation and get responses like this!

      Although I’ve only missed one meal so far, I’m definitely thinking of food a lot at this point. Probably because I’m just hanging around at home, where all the food is. Watching Mrs. MM slurp up a bowl of fresh berries and whipped cream this evening was a mild torture!

      Another factor I’m curious about is whether fasting is easier for people with more stored fat.

      The author of the Harper’s article referenced sounded like he had dozens of pounds of the stuff – he went from 160 to 136 during his fast. Mr. HirsutePirsute was slimmer to begin with, but he still had at least a few pockets available to burn due to some fun he’s been having this summer.

      Meanwhile at my current starting weight of 171, I had already almost run out of fat, with veins protruding in odd places (I was about 190 in “normal” condition before dropping the bread). Where would the calories come from during a longer fast? Hopefully not from stuff I actually want to keep!

      But this is probably just my wimpiness talking again, as really skinny people have fasted successfully many times in the past.

      15 hours into the fast, I can see this is mostly a psychological battle at first. After all, being an eating enthusiast, I’ve never missed a meal in my life. How difficult is it to break a 38-year habit?

      On the practical side, knowing that it’s only a mental, not physical barrier that stands between me and eating at much longer intervals is extremely handy! On a business trip or a long drive, you just strategically fast until a source of good food is available. When camping overnight, if you’re too busy to pack all those meals, hell – just make a fast out of it!

      I honestly didn’t know that an active person could skip food for 24 hours without causing some damage to himself. Plus, it might even help us live longer and healthier lives. This knowledge will definitely be a source of power.

      • SunTzuWarmaster August 25, 2012, 10:41 am

        I did a 3-day fast a while ago or so, and it was truely eye-opening.

        Firstly, I only eat one meal daily. This has had several benefits. The first is monetary (you simply eat less). The second is time, as you prepare less meals, less often, and do not have to stop to eat them (this goes triple for something like “going out for lunch”). The third is health, as, in general, I found that I get to be a normal-ish weight under this plan. The fourth is self discipline.

        One of the things that you notice when fasting is just _how much_ food is available. Another is just how much people seem to need to eat (people complain about missing breakfast? Seriously?). Another is just how little you need to eat. Knowing that you can go a full day (24 hours) without food is powerful, and it makes it so that you don’t base your plans around it, and instead treat eating as a luxury (The Stoic in you would be proud).

        Knowing I can go three days without eating is a huge source of comfort.

      • Sheepfugue August 25, 2012, 7:37 pm

        The master I study Tae Kwon Do with is muslim so he fasts during the day for the holidays. He doesn’t even drink water while teaching about six classes throughout the day. Some students worried about him but he said it was not dangerous and was good for your body, like changing your car’s oil. When I’ve tried it myself I mostly like simply having one less thing to think about during the day.

        I’ve noticed of course that my appetite goes up with my physical activity but conversely I’ve found that when I’m regularly eating the bare minimum (times of under-employment in the past, for example), my hands are stronger. Not sure if that means anything.

        For a different view, folks might want to read The Great Starvation Experiment which is about experiments they did with conscientious objectors during WWII. Long-term starvation can lead to less productive output and less social behaviour without the victims’ even realizing it. (I certainly get sick of co-workers who brag about being on a diet and then get snippy with everyone and don’t notice the connection…)

      • Bakari August 25, 2012, 10:51 pm

        I kind of suspect it is even harder for people with more fat to burn – a natural predisposition to hunger even when their body doesn’t need calories is one of (if not the) largest contributors to obesity.
        “Where would the calories come from during a longer fast? Hopefully not from stuff I actually want to keep!”
        Yep, afraid so. Once you run out of fat stores under the skin, and mixed in around muscle, and in the liver, then your body starts breaking down muscle for energy.
        But then you can always gain it back again with a bunch of hardwork and protein after the fast is over.
        “I honestly didn’t know that an active person could skip food for 24 hours without causing some damage to himself.”
        Seriously? 24hours? How would man kind have existed the 10,000 years before agriculture and food storage was invented? I know there are lots of people who seem to think they will die if they miss a single meal and have low blood sugar, but I would never have expected the great MMM to be among them! Why, you were even the one who gave us the best dieting concept ever: “learn to appreciate mild hunger”.
        My fat management blog post is pretty much all about ways to minimize hunger in a calorie deficit. Most of it won’t apply to full on fasting, but you may find something interesting there none-the-less.
        Its long and has charts and graphics and lots of references.
        Its the hyperlink when you click my name at the beginning of the comment.

      • Dan August 27, 2012, 12:45 pm

        Really, I’m amazed that MMM has been able to eat 3+ meals a day as a fat burner. I’ve been trying primal/paleo for a while now and it makes me ill to even think about eating “three squares”. I basically just eat whenever is convenient without much thought of the quantity (in a reversal from the S.A.D. it’s all about the quality). Food is now equivalent to brushing my teeth in that I do it because I’m pretty sure I will regret it later if I don’t.

        • Mr. Money Mustache August 27, 2012, 5:25 pm

          Bakari – you are right: this was a giant hole in my understanding of nutrition that should be mocked – and I’m glad to be filling it in now.

          To be clear, I didn’t think there was any PERMANENT damage from fasting, but I thought it would lead to some sort of muscle loss and long-lasting metabolism drop that would tend to make the body more likely to store fat in the future (as described in explanations of why sporadic dieting generally fails).

          Dan – I find the high-fat/low-carb diet does indeed lead me to skip meals. But only on inactive days. Today, for example, was a bit of a computer day for me, and sure enough I ate very little. Some days last week involved a lot of physical work and some weightlifting and biking, and they were 3+ meal days (depending on the meal size).

          • MrsTrimWaistFatWallet September 1, 2012, 6:32 pm

            No metabolism loss, your body will the same, but yes you risk muscle loss. It’s basically the same as training for a race except at a slower pace. When I trained for the Ironman, I’d go through my glycogen stores during a workout even (often up to 7 hr workouts) then my body would eventually work at muscle. Despite 6 months of running, biking, and swimming, I LOST muscle mass. So, if you’re concerned with muscle loss, be sure to eventually equalize your calorie intake and hit the weights to rebuild.

      • James August 28, 2012, 5:11 pm

        Worth noting that your friend’s weight loss during the fast will be mostly water. Carbohydrates in your body bind to water, and is one of the first energy stores to be used up in a fasted state. You burn the carbs, you drop the water. It’s why people on Keto or other low-carb diets commonly drop 6-8lb in the first week, only a bit of it is fat (and most of that initial loss will come back when you start eating carbs again)

    • Jeh August 25, 2012, 6:10 am

      Dragline is absolutely right. You don’t get all of the true benefits of fasting, nor experience the amazing states of mind it puts you in, until after 72 hours or so. By then you don’t really feel like eating at all.

  • Mr. Risky Startup August 24, 2012, 9:06 pm

    Spending years in the longest city siege in modern history (Sarajevo in the 90’s), we quickly run out of food we had stored and started to live off scraps delivered by UN and our inventiveness. Here they kill dandelions as weeds, back there they were only food many days. Funny thing though – food was least of our concerns. After first couple of weeks, you learn that amounts of food we ate pre-war (about 1/3 of what average American eats every day) was way above what we really needed to survive. We had days without any food, and when we did eat, it was one can of spam divided among 5-6 people.

    Still, I never remember being actually hungry, and I do not know of anyone who actually died from disease during the war. Someone once said that if humans could eat and shit like birds, we would all live well over 100 years. Now, when I have plenty of food, I catch myself being “hungry” almost every day?

    Food is the necessary evil – it keeps us alive and killing us at the same time.

    • Fangs August 25, 2012, 5:10 pm

      Birds have to usually eat close to their own weight every day.

      • Bakari August 25, 2012, 10:58 pm

        Birds weigh very little, and it takes a huge amount of energy to fly.

        • ErikZ August 30, 2012, 8:30 am

          Maybe he means by slamming your face into your plate to eat the food?

          I know that would make me eat less.

          • pbooker683 September 28, 2015, 11:23 am

            Now THIS is a hilarious comment! I have been snorting at my desk since reading it.

  • James August 24, 2012, 9:15 pm

    Great plan, I’ve fasted many times starting when I was just a kid. My favorite is a juice fast, but a full fast is a good way to start and learn how your body reacts. I don’t really consider 24 hours a “fast”, it’s just enough time to get good and hungry. :) It’s on day three that you really appreciate what a “fast” is and the unique feelings it provides. And I won’t consider you badass in fasting until you have gone at least a week.

    Enjoy it and try it with variable properties until you find one that works for you. A good fast once or twice a year is great, though I think a 3 day fast once a month would be perfect for me if I’d only do it.

  • Ross August 24, 2012, 9:59 pm

    What a good post on a great topic. And if I’m honest, I’m kind of slightly surprised that it hasn’t come up in the past. The topic is so similar to other concepts that have been discussed here: living not on what you _want_, but what you _need_. And in today’s American culture, what people think they need is disgustingly out of proportion, especially in reference to food.

    I think this goes along great with the post on your body adapting to summer heat, MMM. Once your body gets accustomed to having less food (not in any self-deprivation way or anything), you don’t mind not eating and as a result your body enjoys the freedom of not always eating and at the same time enjoys the benefit of food when you eat.

    I can only speak for myself, but I’m a very lean and athletic 6’1″ and 160lbs and have no qualms with missing multiple meals in a row. I really don’t have a solid reason (currently, anyway) to force myself to skip more, but on the days where I don’t eat, it is no big deal at all. I love being able to enjoy the freedom of controlling my own body and giving it food when _I_ want, not letting it dictate that to me.

  • Teresita August 24, 2012, 10:03 pm

    Good for you, MMM! Go for it.

    You can translate a food fast into every other area of life, for deeper appreciation of what you have as well as for personal growth: abstain from phone calls, checking email, listening to music, powering up your favorite hand tools (try it for a week, I think you’ll find it extremely difficult…don’t even pick up a hammer), checking bank balances, etc. Back in the ’90’s one of my high school students gave up speaking for several weeks, as a discipline. He still functioned well in class; he just wrote or pantomimed.

    A speaking fast wouldn’t work very well for most females. We’d reach critical mass after about 16 hours….then….


    I tried a speaking, computer, social visiting, and phone call fast for two days several years ago and I did OK, but I had to talk to the cashiers at the bookstore and the grocery store to make my transactions. It probably prevented the pressure of unused words from causing my cranium to explode.

  • George August 24, 2012, 10:19 pm

    Around 2006-2007, I did a one week fast for fun just to see what happens.

    I used my juicer to juice various types of veggies and fruits, also I drank milk, no solid foods allowed.

    The hardest part was sleeping at night, your stomach will growl for food and you get all these weird dreams. Since I was eating no solid foods, I stopped having any bowel movements for a week as well.

    One thing to note is that the first regular meal you have after coming off your fast will upset your stomach; this is because you go OMG food!! and then eat a big meal, then your stomach is like ‘oh crap solid food again after one week of just liquid, what do we do?’ And then you end up with a big stomach ache while the body readjusts to solid food again.

    To be honest I did not notice that much in terms of health effects or benefits, prob lost about 10 lbs; sorry to bust your bubble but I did not have any religious experience or life changing thoughts, it was nice to know though that you can do it just for personal pride.

    Another thing to point out is that on the juice diet, it is actually quiet expensive; just trying going into the produce section of the store and buying enough produce to juice for a solid week, prob spend $200 back then, of course, this was in my pre-MMM life when I was not trying to save money that hard; see you can juice just straight carrots or celery (both of which are cheap) but it tastes like crap just by themselves alone; thus you need to add some fruit as a sweetener into the juice concoction in order to make it bearable to drink in large qualities, this is where the cost goes up; plus I was trying tropical or alittle bit more exotic fruits for juicing as well during that week just to keep it fun that also made it more expensive

    • Jeh August 25, 2012, 6:14 am

      There are such things as juice fasts, though it’s not an “anything goes” type of deal. But milk? Sorry, that’s not a fast…at all.

  • Sekenre August 25, 2012, 4:34 am

    Here’s a link to a study done on a 27 year old man who fasted continuously for over 1 year and lost 275 lbs:


    I regularly fast each year for religious reasons, 3 weeks of no eating or drinking between sunrise and sunset. I don’t find that I lose much weight on this, but I’m not paying attention to that aspect.

    I find the Eat-stop-eat intermittent fasting plan very effective, similar to the final diet in the BBC documentary above. I need to get a new hole punched in my belt soon so my trousers don’t fall down.

    I find it really wierd to be out wandering in my hometown and be surrounded by people chewing on something! It’s like if their jaws aren’t working, they’ll drop dead on the spot!

  • Jeh August 25, 2012, 6:04 am

    Fasting is indeed badass! So glad you chose to write about it here.

    I’ve fasted off and on (mostly off) over the last 15 years or so, usually a 3 day fast done sporadically. But back in May I decided (for spiritual, health, and psychological reasons) to begin doing regular 24 hour water fasts once a week and have kept that schedule ever since. I’ve also managed a 7 day fast during that time frame. I won’t go into the nitty-gritty, but the results have indeed been badass, spiritually, physically, and emotionally. My wife also has done the occasional fast with me and we’re intend to keep it up from here on.

    About a month ago we finished one of the best books I’ve ever read on fasting called ‘The Transformational Power of Fasting: The Way to Spiritual, Physical, and Emotional Rejuvenation’ by Stephen Harrod Buhner. I highly recommend this great little book to anyone who is badass enough to start fasting regularly!

    Disclaimer: disclaimers to “talk to your doctor before attempting to do anything” is decidedly not badass. Just sayin’…

  • Gerry Born August 25, 2012, 6:18 am

    In January of 2011 I started the Slow Carb diet and promptly lost 30 lbs. I have also experimented with intermittent fasting; usually doing a 24 to 48 hour fast. To my surprise, it is not very difficult to do once you are “fat adapted.” Paleo, primal and slow carb dieters should be able to fast quite easily since their bodies are already accustomed to burning their own fuel–fat. As a guy who grew up in New Orleans eating tons of good food, I never envisioned myself fasting, but now I plan on fasting a couple of time a month. Give it a try.

  • aspiringyogini August 25, 2012, 6:20 am

    I do a 5 day fast twice each year, at the beginning and end of the summer, and have done this for many years. I do this as a detox and also to continue to prove to myself that I am allergic to dairy. The most important part of the fast diagnostically is the reintroduction part. Of course, as a previous commenter mentioned, you have to go very slow, or you will suffer. I have a list of the top food allergens and I introduce each one by eating a small amount alone and watching for increase in heart rate (check before and 20 min after eating) or in my case allergic rhinitis or sinusitis. Every time I reintroduce yogurt or milk, I get with a runny nose or post-nasal drip. While fasting and as long as I don’t eat dairy my sinuses are in good shape.

    There are lots of programs that include fasting such as Master Cleanse and the one I follow, “The Fasting Diet” by Steven Bailey. I like the second one the best because it includes juicing, which allows me to keep working and doing a couple hours of exercise daily. It seems much harder than it really is, since the “suffering” people describe is more psychological than physical. I have two friends who have gone 30 (or more) day fasts, one does it while observing lent (40 days) and the other did 30 days of Master Cleanse, mainly to lose weight. One of my students told me about how she observes Ramadan, eating only one small meal at night for that holy month; the challenge here is to not overdo it at night.

    Now my husband, who has watched me do this for years, is now on his last day of the fast and he’s amazed that it is not so difficult. He is doing this because he has had heartburn and indigestion for 6 weeks that wasn’t improving with OTC antacids and acid reducers. Now, he is feeling much better and is below the weight he was when he was a competitive volleyballer. I would guess that his previously elevated glucose, cholesterol and lipid levels are reduced in addition to the weight loss.

    I think that fasting is a good thing to do every so often and I redevelop a deep respect for food during and after I am done. I also think of the people of the world who cannot do this voluntarily; they just have to go without or make due with what they have.

  • Claire August 25, 2012, 6:30 am

    Well you’ve convinced me to give fasting a (micro) trial! I’ve read about it time and time again and although I saw the merits, my bad-ass-levels were just too low at the time. I think I’ll do a 24 hour water (and tea!) fast starting now. It’s time for a level-up.

  • Stephen August 25, 2012, 6:55 am

    I’ve been reading about this and other beneficial stressors over at gettingstronger.org by Todd Becker. If you like what he says, maybe there could be a guest post?

  • westerndog August 25, 2012, 6:56 am

    Hatorade Alert!!
    Many of these comments and observations are scientifically unsound. A normal sedentary person can have 1300+ calories in glycogen storage, and a well trained athlete can have in excess of 2000 calories-all stored just in liver and muscle glycogen (ie, sugar). That is more than enough for 24+ hours of basal metabolism for most weighing150-160 pounds or less.
    Even in extremely lean athletes, there is enough energy in fat to last for days (if not weeks if adequate fluid available)-that explains the ability to perform extreme endurance sports-Ultraman, 100 mile races, etc.
    The drawback is that your body is extremely efficient and will actually cannabilize its own protein stores (ie, muscle).
    So prolonged fasts are really an extremely poor way to lose weight-you will lose muscle, water, and glycogen, but not much in the way of fat.
    Much more efficient would be frequent long bouts (1.5-2+ hours) of low to moderate intensity aerobic exercise coupled with short bouts of high intensity workouts.

    • Mr. Money Mustache August 25, 2012, 7:17 am

      Yeah, I’m definitely aware of that “eating your own muscle” issue. I don’t think fasting is a great idea as a primary fat loss technique – for that I firmly believe in weight training a few times per week combined with a normal but low/slow-carb diet. (And generally moving about whenever you can all day to form the low-intensity portion of the work).

      To me, this is more of a mental exercise – seeing if I can break such a strong habit at will. (I’ll also be breaking my daily coffee habit as part of it). And don’t forget the studies cited in that Harper’s link relating to longevity in animals (and disease in humans too). Those seem pretty significant to me and worth learning more about.

      • Dragline August 25, 2012, 10:36 am

        I think that concern (eating your muscles away) is a bit overblown unless you are training for some event or are body building.

        But the “cleansing effect” is well-known and generally is attributed to autophagy. Your cells literally munch on old, bad proteins and other refuse, helping reduce inflammation and improves resistance to degenerative diseases. There has been a lot of research about the benefits of autophagy in recent years.

        In the 19th Century it was common knowledge that fasting for a few days would cure most common ills and generally improve one’s health (if one was otherwise healthy). Mark Twain was a big proponent of it. See http://www.twainquotes.com/Bradley/PhysicalCulture.html

        Of course, we have to remember that the medicines available at the time were often little more than poisons and alcohol, so a little fasting was often the best alternative.

      • Debbie M August 25, 2012, 6:03 pm

        Caffeine withdrawal has its own side effects.

    • aspiringyogini August 25, 2012, 8:08 am

      I’m not sure of which comments you consider to be unsound and unscientific. However, if you are referring to fasting for weight loss, this doesn’t make any sense, because there will very likely be a rebound effect and muscle breakdown as you describe.

      Fasting is used a lot medically. When people or animals have vomiting and diarrhea it is recommended that they not eat anything for 12-24 hours and slowly introduce water when they feel better. Prior to blood work and surgery, people are required to fast. A friend of mine who has Crohn Disease went 6 months where she connected to a catheter at night and received IV nutrition and could only take in clear liquids during the day and her chronic intestinal inflammation calmed itself considerably. After my father had his cecum and right colon removed because of cancer, he was only allowed to take in fluids the first time 36 hours after surgery and then only fluids for 2 days, before moving on to pureed veggies and jello.

      Also, since many people and animals are being made sick from impure food, they can often see improvement in their conditions when they fast for short periods of time.

      There is a lot of work required to digest food and taking a break from food can allow the gastrointestinal track a much deserved rest while diseased tissue heals on its own.

      • Emmers August 26, 2012, 7:50 pm

        Is it really valid to compare a person with Crohn’s Disease and a PICC line to someone who is consuming no nutrition at all?

    • ErikZ August 30, 2012, 8:50 am

      I’m about 30 pounds overweight.

      I can see where the body would go for the easy glycogen reserves, but shouldn’t it be hitting the fat reserves at some point before the glycogen runs out?

  • rjack August 25, 2012, 7:27 am

    I love it when all the things I like converge – MMM badassity, paleo/primal lifestyle, stoicism, and Zen.

    Mark Sisson of Marks Daily Apple wrote an excellent series on Intermittent Fasting that starts here:


  • Jack August 25, 2012, 7:45 am

    I was too obese for the army when Vietnam was the current war. I’ve done a few 10-day fasts and lots of 3-day or less fasts. Usually the second day is the most difficult. Its very important to drink 80 ounces or more of water per day. Avoid other liquids, especially diet or regular carbonated drinks. The water washes the byproducts of fat conversion to energy out of the body. Not drinking sufficient water can cause kidney damage. I used the Doctor’s Quick Weightloss Diet (http://www.amazon.com/Doctors-Quick-Weight-Loss-Diet/dp/0440120454/ref=sr_1_1?s=books&ie=UTF8&qid=1345902086&sr=1-1&keywords=doctors+quick+weight+loss+diet) to go from 210 pounds to 154 pounds in 4 months. The diet starts with a 3-day fast.

  • Mike August 25, 2012, 9:15 am

    I’ve done several three-day fasts and they always make me feel better– lighter, more energetic, and more connected to myself and the world around me. I know that sounds a little new age or something, but I think it is about right. I usually fast a couple of times a year.

    Having now done 20+ days on a whole foods diet (primal +), I’m convinced I have at least one food allergy, so that might actually account for why the fasts made me feel that way, as it might be less about the fast and more about just cutting out the source of my allergy (dairy and gluten).

    I’m continuing to post about my 30-day whole food change for those who might want to read about it. http://livetheneweconomy.com/health-and-wellness/

  • totoro August 25, 2012, 10:11 am

    I don’t fast but I sometimes forget to eat for a whole day when I’m engaged in particularly interesting problem solving or when I’m under stress. I also don’t eat breakfast because I don’t get hungry in the morning.

    I have dealt with all sorts of comments on how I eat, particularly how unhealthy it is not to eat breakfast. My feeling is that I should eat when I’m hungry and forcing myself to eat when I’m not seems silly given that our body gives us cues.

    At 40 I am normal weight for my height and healthy. I have not had any issues with weight gain throughout my life except when in my early twenties I decided to go on a diet. All of a sudden I gained weight after switching to a low fat diet. Never again.

    I eat a healthy diet and full-fat everything with no artificial sweeteners and very little processed anything. The only ill effect I notice from skipping meals is that I’m hungrier than normal the next day.

    • Bakari August 25, 2012, 6:09 pm

      Everyone eats breakfast. There is no possible way to avoid it.

      When ever you eat the first thing for the day, you are “break”ing your “fast”
      You just have break-fast later in the day than most people.

      • Dillon August 26, 2012, 10:59 am

        C’mon, you knew what was meant. Not every word can be broken down to the original literal meaning and mean the exact same.

        Even for those that don’t subscribe to eating 3 meals every day can usually infer from context what was being meant. Hypothetically, if you only eat 1 meal per day at say, 4 p.m. and call it breakfast, you’re either being obstinate about the social norm, work/live different hours than most, or you just like being different (which is fine, but you shouldn’t become the Meal Police and call out other people when it is apparent what they meant, and what was said would be comprehensible by most when talking about food).

        • Bakari August 26, 2012, 7:57 pm

          Meal police? My point was to defend Totoro, against all the people who claim its somehow unhealthy to skip breakfast. Totoro is eating breakfast, just later in the day than they choose to eat it.
          People are always claiming such and such is unhealthy, but you have to be able to point to some sort of supposed effect and some potential mechanism of action to cause that effect.
          In many modern cultures we have developed a norm of exactly 3 meals a day, specifically at about 6-9am, 12-1pm, and 5-7pm. Those are totally arbitrary and based on nothing. So, when I say eating breakfast later is still eating breakfast, I don’t think its just semantics, I actually meant to point out the arbitrariness of saying everyone must eat a meal between 6am and 9am.

    • TB at BlueCollarWorkman August 27, 2012, 8:23 am

      My sister is a scientist and talks about this kinda stuff a lot. She says that the whole “not eating breakfast is unhealthy” thing stemmed from research showing a correlation between people who eat breakfast and having a lower average weight. But, she always points out that correlation does NOT imply causation (does eating breakfast make you skinny? or do skinny people have some other physiological factor making breakfast more appealing to them? or…? — the correlation of skinny ppl and breakfast eating has no cause indicated from teh research). And so this eventually got turned into “not eating breakfast is unhelathy!” So don’t worry about it, as per usual, the media took some research, mis-interpreted it, and it keeps getting repeated. If you don’t like breakfast, then don’t eat it. :-)

  • stu August 25, 2012, 10:14 am

    While not fasting, I’d have to say Veganism is a another mode of badassity. Dairy is in most processed foods so that eliminates them from your diet. Also, your grocery bill is slashed with buying fresh fruits and vegetables, nuts and grains. I was meat eating guy would loved to bbq, but have been overweight all my life, it’s what works for me. I’ve lost about 70lbs this year and feel amazing! I feel better about not supporting the factory farming of animals in this country. Healthy, economical, and earth friendly, sounds mustachian to me!

  • Yabusame August 25, 2012, 10:19 am

    I’ve toyed with the idea of fasting for many years but never got around to it. I think I’ll give it a go. 1 day of fasting in the first month, 2 in the second, and so on until I get to a full week (maybe).

    I look forward to hearing about your results.

    • Yabusame August 27, 2012, 1:57 pm

      I completed my 2 nights/1 day fast today.

      So how did things go this first time round? Well, I last ate anything at around 21:00 on Saturday 25th August. I weighed myself before going to bed that night and I was 71.2kg (157 lbs). Naturally, I slept well, as it was just an ordinary night’s sleep.

      The day of the fast (Sunday) started with a weigh-in where I was 70.6 kg (156 lbs) and some work on the laptop. Also that morning I did a 3 mile run and a 3 mile cycle ride. Nothing too strenuous, but it felt good. I wasn’t hungry at all in the morning but I started to feel the hunger in the afternoon. I think that was because I was just sitting in front of the TV for the afternoon, thinking about fasting and food in general. My mouth was constantly salivating. As evening drew in, I really started feeling hungry. I went for a couple of short walks but felt restless. The hunger pains started to diminish as the evening passed. I weighed myself again that evening before going to bed and I was 70.7 kg (156 lbs). I had gained 100 grams (3.5 oz) in one day of fasting. I can only guess that this was because of the water I was drinking because I wanted to stay hydrated to prevent headaches and I also drank water whenever I wanted something to eat. Sleep last night included a strange dream in which I was eating a couple of biscuits and as I bit into them I felt guilty because I’d forgotten I was fasting. Dreams are weird ;-)

      Woke up this morning feeling good. No hunger pangs. Weighed myself and I was 69.9 kg (154 lbs). That’s a total weight loss of 1.3 kg (2.8 lbs). I broke my fast, at 10:00, with a bowl of porridge and a bacon sandwich; just like in the Horizon video that Dave posted about earlier in these comments.

      Now I know what to expect from my first day of a fast, I will try 3 nights/2 days later in September. I’ll try to remember to report back here on how that turns out.

  • Christina August 25, 2012, 12:01 pm

    Thanks MMM! I enjoy your posts, and especially love that you’re exploring eating habits; our North American diet is absolutely revolting when taking in the big picture of how the majority of our world eats. We can learn a lot by fasting and realizing what our bodies are actually capable of and in doing so, not consume and dispose of so much food (especially processed food). Fasting is good for our bodies and our minds!
    Thanks for making your readers think and grow our minds – keep it up!

  • Poor Student August 25, 2012, 12:08 pm

    I do not consider myself hydrated unless I have clear or very pale yellow urine. I do not know if fasting would alter the colour but I would be shooting for completely clear urine because I would be drinking a lot more.

    There is water in the foods you eat and at the very least you would have to drink enough extra to replace those fluids, as well as any non-water beverages you gave up and you likely would be drinking more water to stave off hunger pangs.

    Maybe someone more familiar with fasting could clarify this? During a fast seems the most important time to be hydrated and the author states his piss was golden as normal. That to me doesn’t seem like enough hydration.

    But overall I found this interesting and may be the kick in the butt I need to finally do a fast of my own. I am an admitted food lover, I know that the healthiest way to look at food is simply as fuel but probably 80% of my thoughts are devoted to what I am going to eat next.

    • Joy August 25, 2012, 3:09 pm

      One can dilute the solutes to the point of determent.
      Be careful.

      • Dillon August 26, 2012, 11:40 am

        Poor Student: I am the same way with my urine. haha, that was a funny sentence to type. I also thought the mention of the adjective golden was a temporary eyebrow-raiser but nothing to suggest there was something wrong with the author. I just thought maybe I over-analyze my fluid intake/urine output too much but I’m glad someone else mentioned it.

        Joy: What does that mean? Are you saying it is better to err on the side of dehydration than it is to drink too much water? How does one know when they have diluted their solutes so much that they find themselves at the “Point of Determent”? What happens, uncontrollable bed-wetting, 2 minute long pisses in the bar bathroom, leakage, something worse?

        • Poor Student August 26, 2012, 6:08 pm

          I know others do not worry about how much fluid they intake as much as I do but I know that it is something they should. I read somewhere that North Americans in general are so chronically dehydrated they often mistake thirst for hunger. I was just guessing that on a fast one would be even more concerned with hydration than I am on a normal day. And I guess I need to take into consideration that the author might be hydrated and have a different colour urine than I. To each his own.

          Joy:I have heard of some cautions from people thinking I drink too much water. I used to carry around a 4L jug at school. Of course I worked out and played sports and am larger than average as well. But I never heard of the “Point of Determent” and when I search it nothing comes up. I know the harmful effects of over hydration but if you could explain this one?

          • Bakari August 26, 2012, 7:38 pm

            The best way to tell if you need to drink more is if you are thirsty.
            The best way to tell if you are properly hydrated is if you are no longer thirsty.
            There is no medically recognized benefit to forcing yourself to drink more than your body asks for, despite the extreme common folk knowledge that you should:



            “North Americans… often mistake thirst for hunger” That’s probably true, but not necessarily because of dehydration. Many American’s drink exclusively caloric beverages – soda, juice, milk, coffee or tea with cream and sugar – so the body learns eventually that hydration and calories are linked. I personally discovered that when I started drinking water instead of juice, I was thirsty less often, but craved fruit more often. I think my body adjusted to realizing fruit was now the source of vitamins that I had been getting from fruit.

            • Uncephalized August 26, 2012, 10:26 pm

              Most people also don’t know that being overhydrated is just as bad for you as dehydration–and it can also kill you. Look up hyponatremia. Drinking too much water dilutes the electrolytes in your blood and cells and messes up a whole bunch of essential processes.

              If your urine is clear all the time you are probably drinking too much water.

            • Poor Student August 27, 2012, 5:00 am

              If you are thirsty you are already dehydrated, not by much but it is a sign we are. It is like shivering when you are cold, you shiver once you are already cold not when you are about to become cold.



              Drinking before you are thirsty will prevent dehydration as opposed to remedying it.

            • Bakari August 27, 2012, 10:24 am

              That article has no scientific credibility! The “Dr” claims that water is a source of “energy”, and sites “an experiment” (but not who or when). He is promoting his own website – and from their his own book.

              All the stuff he claims is explicitly addressed in the articles I posted – and they do list their references, so you can check if they are just making stuff up. Having been to med school does not make a person’s personal opinion into biological fact.

  • Joe Rodriguez August 25, 2012, 1:37 pm

    A great post. Fasting is a very old, but becoming a very popular trend again.

    Not sure where this idea of “72 hours” is coming from, does anyone have a link for some research? Literature I’ve seen shows benefits from about 18 hours up to 36; while there may be additional benefit after 36 (insulin sensitivity, etc etc…) – there’s also muscle wasting and things of that like to deal with.

    In addition (and I don’t have a source for this, just from books and general knowledge) – I’ve heard it discussed that in general, the less you eat, the longer you live. I’ve picked this up in conversations with Dietitians as well as in books like “Born to Run” and “Thrive” by Brendan Brazier.

    • Dragline August 25, 2012, 9:53 pm

      There is an entire group of people devoted to living longer through calorie restriction. Website is here: http://www.crsociety.org/ If any of you thought you were obsessive, you have nothing on these people. I don’t practice CR myself, but there is much to be learned from them and the doctors who study them. There is a lot of ongoing research in this area.

      72 hours gets you to the place where you stop feeling hunger pains. And into autophagy. Look up autophagy. Studies like this: http://www.ncbi.nlm.nih.gov/pubmed/20534972

      You’re not going to have muscle wasting from fasting unless you are dying of a degenerative disease or are on some kind of an extended hunger strike. Don’t believe the hype on that.

  • Marcia @Frugal Healthy Simple August 25, 2012, 2:44 pm

    I’ve been reading about fasting on Mark’s Daily Apple. I’ve never intentionally fasted, except to have bloodwork done. I understand there can be differences between the effects on men and women.

    In any event, I won’t be fasting until I’m done nursing. So, maybe I’ll revisit this post (and any followups), sometime in a year or so.

    • Lurker August 25, 2012, 6:01 pm

      I was wondering about that. I’m currently nursing my 5 month old and don’t know how fasting would affect the quality of my milk. It seems like a bad idea.

      • aspiringyogini August 26, 2012, 4:47 am

        In dairy cows, when we want to dry up milk production (usually in order to get the cow pregnant again), we will keep the cow off food for 24 – 48 hours. This usually slows and then stops milk production and the udder won’t get engorged from not milking. This seems like it would be the same for people as well. Perhaps one could ask a lactation expert?

    • cptacek September 11, 2012, 10:06 am

      I have not fasted while nursing, but I did start on the Atkins 1st phase while nursing, and I saw an immediate drop in production. Before, I was able to pump all I needed in one 15 minute session and got about 10 ounces at a time. 3 days after I started the Atkins diet, I had to go up to two pumping sessions and was only getting about 4 ounces total. I increased my carbs and I didn’t lose any more ounces, and eventually I got it increased to the 6 or so ounces he needed by then (he was 6-12 months during this time period, so I had started introducing solid food), but it never rebounded to the 10 ounces I saw before.

      Please be careful! :)

  • Bakari August 25, 2012, 6:00 pm

    Funny you should write this now.
    Just yesterday I was building a deck. I had started around 9:30am, (having had a bowl of granola for breakfast), and I was close to finishing the project and wanted to get it all done and over with, so I tuned down all offers of food, worked through lunchtime, and worked through dinner time. As it started to get dark the person I was building for insisted that if I wasn’t going to stop and come in, at least she would bring me something, and she made a sandwich I brought it out for me to eat while I was working.
    And she made a comment about it being very impressive that I was able to work so much with so little food, which I found kind of strange, because it really isn’t that hard. You just do it. Your stomach may hurt a little bit when its normal meal time passes, and you ignore it, and after a little while it goes away.
    I’ve come to realize the whole reason that people feel the need to eat so often is they have trained their bodies to get used to it. The whole feeling weird from low-blood-sugar thing, that couldn’t possibly be natural, because if it was, whenever our ancestors didn’t have plenty of food, they would get light-headed and irritable and whatever else, and they would be less able to acquire food, and it would be an escalating cycle ending in starvation. All it takes is some practice, and anyone (save diabetics) can break themselves of the blood sugar addiction, and then you can just eat when its convenient.
    Much like the two people in this article, I decided to try a calorie restriction diet a few months ago, partly because I had gained an extra couple percents of bodyfat, but mostly for the challenge and the experience. I kicked it off with a 48hour fast, and then kept eating less than maintenance calories for a week and a half. I have to admit, it was harder than I expected. You think about food constantly. And this was me, who can eat 6 meals a day or 1 meal a day and not think twice about it. Chronic calorie deficit really got to me. Made me more sympathetic to overweight people. It sucks being hungry all the time, and that’s pretty much what it takes to lose significant amounts of stored fat. It also reinforced my commitment to never let myself get to a point where I need to lose excess fat in the first place. I know I could do it, but I sure as heck don’t want to have to!

  • Shilpan August 26, 2012, 8:50 am

    I’ve been fasting every Tuesday for last six months. I also am walking on average 16K steps per day. These two changes alone without any exercise have helped me lose over 20 pounds. I used to weigh 173 lb. Now, I weigh around 150 lb.

    I think fasting is a wonderful way to rejuvenate your mind, body and soul.

    • Oh Yonghao October 9, 2014, 3:02 pm

      You sort of contradicted yourself by saying that you walk over 16K steps per day then say that you have lost weight without any exercise. On my blog, which is linked to in my name, I have an article about the only diet that works and explain how every diet is reduced to two things: 1) Calorie restriction, and 2) Exercise. Fasting every Tuesday is a Calorie restriction, and walking 16K steps a day is exercise.

  • mike crosby August 26, 2012, 5:26 pm

    This is the largest/best fasting health center in the United States: http://www.healthpromoting.com/. I’m not at all affiliated with them, but I could not give a more higher recommendation.

    We can try pills and what have you to get our health back, or to reach our upper limits on health, but fasting is by far the best thing we can do for our bodies. Nothing else comes even close.

    Kudos to MMM discussing fasting. The best book that I’ve ever read on fasting is “Fasting and Eating for Health” by Dr Joel Fuhrman.

    Years ago, an opportunity presented itself for me to fast. On my first day of the fast, I found Dr Fuhrman’s book in my local library. As I was doing the fast, I read and reread the book. And I thought to myself, if just a bit of this is true, it’s incredible.

    One of my favorite quotes in the book: You can’t escape the biological laws of cause and effect. (You’ll have to read the book to see a more in-depth discussion of that quote.)

    If anyone is interested in going to the health promoting website I linked above, after you linked there, click on “Learning Center” and then click on “Articles”. Tons of excellent information.

  • Rose August 26, 2012, 7:25 pm

    More great information in the comments, as usual!

    Just a reminder to pay close attention to your body during a fast.

    Each day during my three day fast felt very different. The first was only mildly uncomfortable, but the second was more difficult. I had a mild headache all day and very low energy. When I took the dog for a walk, my heart rate was too fast for the amount of exercise I was doing, I was short of breath, and I eventually had to sit down until a dizzy spell passed. This being January in the northern U.S., I noticed my body got much colder much faster and it was difficult to raise my body temperature back to a normal level. That evening I had intense dreams about food. When I awoke on the third day, I felt weak but the hunger pains had subsided, and I was mentally much stronger. As long as I wasn’t doing anything physical, I felt fine, and I could have continued the fast for a fourth or fifth day. Knowing that, making the choice to end it after three days felt rewarding enough for a first attempt.

  • PFgal August 26, 2012, 7:37 pm

    Has no one else here fasted for the Jewish holidays? I haven’t done this in years, but I did when I was younger. It seems so odd to me that there are people who *haven’t* fasted for at least 24 hours before. At first it was tough, but I soon learned that I’d be fine physically and that it was all in my head. Of course, everywhere I looked there was a reference to food – on tv, in a book – but once you get past that, it’s not so bad. I have my doubts about the healthfulness of long fasts, but certainly not eating for a day occasionally is not a problem – it’s a regular occurrence in many religions that people have practiced for millennia.

  • OWHL August 27, 2012, 7:38 am

    One must be aware of the activity being pursued while fasting. Fasting for spiritual means have in general, incorporated a non-active lifestyle for that time. In other words, meditating or doing a passive yoga routine only while on a fast. Otherwise, you risk the dangers of damaging your body- of course this this is towards the people who do not pay attention to how their body reacts. There is certainly something beneficial to fasting when done correctly. If you need more motivation I would suggest the Vedics or Yogi teachings- almost any Eastern philosophy has something important to say on the subject.

  • TB at BlueCollarWorkman August 27, 2012, 8:13 am

    Right on. Our bodies are evolved for feast or famine. And in our culture these days, there’s almost never a famine. So I think it’s great to re-introduce “famine” into our regime. I think until you get used to what yoru body does during food deprivation, you do have to be careful about driving and doing dangerous stuff (just for the 1st or 2nd fast until you know better what your body acts like), but otehrwise, yeah dude, fast on! (and as a side bar, like you said, it IS a nice reminder of how much we have in our cushy lives and can only make us more grateful!).

  • Mr. Everyday Dollar August 27, 2012, 8:32 am

    I will be going on a solo quest next year where I fast for 4 days PLUS I will be in a forest constrained to a 12 foot circle with no outside contact. The only reason to leave the circle will be to use the latrine. All I will have with me will be clothes, a sleeping bag, all the water I can drink and my thoughts. I am really looking forward to this experience!

    Anyone else done this?

    • Heath August 27, 2012, 12:15 pm

      That sounds rad, and somehow very Mustachian! What will you do if it rains? Perhaps that’s not an issue at this time of year, in your particular forest…

      • Mr. Everyday Dollar August 28, 2012, 8:02 am

        Very good question! And I don’t know. It’s in the southern Sierras and I’m not sure about rainfall. Perhaps if it does rain you embrace it and become one with mother nature. When’s the last time you actually stayed in the rain? I know for me I get out of it as soon as possible.

  • Heath August 27, 2012, 12:11 pm

    Really cool ideas in both the post and the comments. My parents were/are both hippies, and thus I’ve been witness to various types of fasting throughout my lifetime, but have yet to try any of them myself. I honestly thought of starting a fast this very minute… but then I realized that I have leftovers in the fridge that need to be consumed prior to spoilage. Slight Mustachian dillema! But not wasting food is more important than experiments which can easily be performed in the near future. So I’m going to not eat anything for the entire day this coming Wednesday. From dinner Tuesday night (7pm), until breakfast on Thursday morning (7am); 36 hours. If that works out, I’m totally going to try a 3 day fast later in the month.

    Side note: For whatever reason, I didn’t get an email like I usually do, when this post was published. Feeling curious, I looked back at some other recent posts (from the homepage), and discovered that “Protecting your Money Mustache from Spendy Friends” had a similar blip in the usually consistent reminders. Just an FYI.

  • Vanna August 29, 2012, 6:41 am

    Sorry if this is redundant, I’m getting ready for work and didn’t have time to read all the comments. Shame! I just wanted to remind coffee drinkers that it is a bad idea to cut out your morning coffee cold turkey. It would be counterproductive for what you are trying to accomplish if you are going through caffeine withdrawl the whole time. If your fast is longer than 24 hours you can wean yourself down if you wish to decrease your caffeine intake going forward. If you have no plans of doing that than just keep drinking your coffee while you fast.

    My personal program is: Eat Paleo M-W, Fast on Thursday, Weigh in on Friday mornings, and release the wheels for the weekend.

    I have found that living a double food (and alcohol) life gives me the best of both worlds. Optimal nutrition, a period of deprivation for a cleansing effect, and then indulgence.

    So far I have lost 15 pounds with this lifestyle. And I LOVE doing it.

    • Heath August 29, 2012, 6:49 am

      Your comment was not reduntant, as nobody else had suggested such a lifestyle. It’s quite appealing to me! I could see myself doing something similar in the near future. How long have you been maintaining this weekly pattern?

      Thanks for sharing!

      • Vanna August 29, 2012, 9:06 am

        It has been 4 or 5 months. I highly recommend it!

  • FreeUrChains August 29, 2012, 10:19 am

    A note to those who have any symptom of a sore throat, or long term tonsilitius in my case. I recommend not fasting, but eating lightly and healthy until you are a 100% healed. Also not exercising intensely until you are a 100% cured. Main reason is you are extremely fatigued to begin with because of the constant recovery and repair cycles you body is producing. This causes dehydration as water is used to help repair every cell in your body. Lack of nutrients makes this recovery worse, though when fasting your body will find ways to absorb any nutrient it can.

    Also, when fasting before blood work is drawn. Don’t get poked twice, else you will slowly black out because of low blood sugar.

    For all those that are 100% healthy (for now), have fun challenging yourselves with the 3 day fasts!

  • BadassCPA August 29, 2012, 2:59 pm

    I thoroughly enjoyed this article, and plan to do my own fast sometime soon. I saw this article recently which while not directly related to fasting, is in the same arena:

    “Severe Diet Doesn’t Prolong Life, at Least in Monkeys”


  • Jeff September 18, 2012, 11:20 am

    I really like fasting while camping. It’s much easier to not eat when you don’t have a refrigerator nearby, and it drastically simplifies packing when you don’t need to pack fuel, a stove, pots and pans, food, utensils, soap, etc.

  • superbien September 18, 2012, 12:11 pm

    Thanks for this article, and the comments. I read it, mulled it over, did some research, read a book (Kindle had a free book on Intermittent Fasting), and then took the plunge.

    I made very attainable goals (2 fasts per week, 24 hours, unlimited noncaloric drinks), and decided in advance that I just had to make those goals, and anything else was gravy. I allow myself a splash of milk in my coffee or tea, and I use stevia as sweetener. I exercise like normal, and have not noticed much impact.

    All I can say is thank you guys for the recommendation!! My experience has been so positive so far that I think I have found my solution to my weight issues! I struggle so much on a diet, but fasting is easy! I get so much less hungry when fasting (even just 1-day fast) than when I eat but restrict my calories. It’s like my digestive system just does not wake up until I put food in my mouth, so I don’t really get very hungry. And knowing that I can’t put *anything* in my mouth makes it so very easy to resist the mindless snacking (see food, put food in mouth) and even delicious canapes at a party I went to. This is trippy!

    A trick I learned: warm drinks (black tea, coffee, herbal tea) help but cold drinks trigger hunger; I had a diet root beer, and it really triggered hunger (not sure if it’s the fake sugar or cold).

    I am in my second week (today’s the 1st fast day of the week). The day after the 2nd fast last week, my scale said I had lost over 15 pounds, but I am very skeptical – I figure that’s glycogen reserves (w attached 4 pounds of water weight) and just simply having a “cleansed” digestive system emptied of all the old food. I wouldn’t be surprised if I saw a few pounds of real weight loss though at the end of this week. I’ll let you guys know.

  • DK December 30, 2012, 7:54 pm

    I found this a very interesting read. Seems relevant to the discussion:


  • Burak June 19, 2014, 1:44 am

    Awesome article MMM! As for your friend who tried several days of continuous fasting, somebody who is not trained about being hungry going 3-4 days without food just to see what happens… I would say, wow, that’s just amazing!

    As a comparatively experienced fasting person who regularly fasts around 30-40 days a year starting from my childhood, I can say that it has a lot of benefits:

    Firstly, you don’t waste your money on ridiculous junk occasionally throughout the day if you commit to a 12 to 24 hours of fasting everyday at least for a month. So, your mustache grows to a better badassity. Furthermore, in a strange way, being hungry helps you keep your other spendings lower (I don’t know how and why but this is what happens with me whenever I fast).

    Secondly, you appreciate the food that you are eating much more, even if it’s not your favorite food. For example, I love pizza, and if I eat 3 times a day, which is what I unfortunately do almost all year except for my fasting days, and if one of the meals is pizza, I enjoy it but just casually. However, when I fast, even eating just casual bread (towards which I’m almost natural) is an amazing and delicious experience at the end of a day of fasting. It’s similar to the experience of a stoic exercise, and a mental shift to a degree.

    Third, you start realizing more vividly that there are millions of people (if not billions) on earth who suffer even a much worse hunger than the one you have experimentally while fasting. It helps improve the sense of compassion and responsibility towards helping remove this suffering as much as possible as fellow human beings.

    In addition, although there are a bunch of scientific back-up to the benefits of fasting from a health point of view, I’m not quite well knowledgeable as to how that really works. However, with all the experience I’ve had up to day, I can reassure you that fasting (especially 12-24 hours everyday for a week or even a month), if you do not have any restricting health issues towards it, is very effective to put you back on a better level of health.

    Lastly, through hunger and discipline, a person is trained to be patient and forbearing, so fasting on a regular basis is, in a way, also a cure for impatience and lack of endurance, which double man’s afflictions. I can testify this myself.

    I have never tried several days of fasting myself(at most 24 hours). However, I have many friends who tried it. They say that it is quite useful but you’d better back yourself up with a glass of water at least every 24 hours during a long-fasting trial.

  • Majik August 1, 2014, 7:54 pm

    Random slight off topic comments below:

    I work 11+ hours a day (2 weeks straight) in a reasonably physical job (stores at a minesite in Australia) I have a quick, small, greasy breakfast and nothing much until dinner that night most days (some times out of time to have breakfast a I prefer sleep over eating). I find I have to eat sugar (usually in the form of chocolate) on high physical or mental days, which is 3 times a week when truck arrives and orders need to be done, otherwise I lose too much weight – yes I’m one of THOSE people. I do have a container of nuts to graze on if required and grab bananas when they not green.

    I have been asked on more than one occasion if I have diabetes, based on my water intake. 3-6 litres a day. Then I am told by the medic at work that ‘that is not enough and I should have more’.

    I usually hover around 70-74kg mark, which I view as my ideal weight for my 176 cm, med build frame. After an unknown illness I was 67 kg and rising, when my old work had a medical professional we just called ‘the fat man’ come by. After checking my hydration, bone density and weight (all very official and scientific looking), he advised my 29 year old self that I should be at 65kg! To which I replied, with all my usual tact, to get stuffed! I explained that when I am that weight, I get moody and depressed, my body reacts and vomits randomly and I have bones sticking out in the worst of places (ie I look and feel unhealthy). The reply – “oh, its good you know your own body”. Yet this man was paid by the company to tell ideal weights to all the young men & women at work, the same who are bombarded by unrealistic body image messages via everyday life and most of which who are too insecure to know better.

    I am in the minority when I say I am happy with my body, although I don’t own scales and weigh myself only when I think I have lost too much weight and my clothes are loose and bones showing that I haven’t seen for a while. The tie in to all this I guess is, everyone is different, and to truly get the best out of you and your body is to know it! (so I don’t like my thighs, I did say happy and not think I’m perfect!)

  • nic April 27, 2015, 8:46 am

    The link to the “Benefits of Starving” article no longer works – any chance we could get it updated with a new working link? Cheers!

  • Rob January 16, 2016, 10:06 am

    Looks like the Harper’s link has been taken down on copyright concerns. Here’s a new link that should be more solid (from the author’s webpage): http://media.wix.com/ugd/03997d_422ba2e2c279e899b8d1c3de71f1b1e7.pdf

  • Will Bloomfield June 17, 2016, 9:43 am

    Traditionally, Catholics were to fast every Lent for the 40 days from Ash Wednesday through Easter, which excludes Sundays, which were days to break the fast. But the Catholic fast is not a deprivation of all food; instead, we can eat two small snacks during the day and a simple dinner.

    Doing such a fast for one day is pretty easy; extending it throughout a week gets much harder. But I’ve also found that once you’ve made it through the first week or so, your body starts to adjust and you typically don’t feel much hunger.

    Catholics also had a traditional practice called ember days that included three days of fasting seasonally, i.e., four times a year.

    The thinking behind such traditional and periodic fasts–and other mortifications–is that, without them, we begin to love things rather than God and our neighbor. We become addicted to the pleasures of this world and seek them as ends in themselves, rather than seeking our happiness and joy in God. In the Lenten Fast, we set aside our love for the pleasures of the world and seek our joy in the Resurrection of Christ that we celebrate at Easter. Following the fast, there’s also frequently a feast, which one can appreciate all the more having fasted leading up to it. Fasting also has the benefit of giving us a solidarity with the poor, who fast out of necessity.

    Sadly, Catholics aren’t as badass these days, and all but the most serious have given up the practice of fasting, which used to be required. But there are some of us “traditional” Catholics that are trying to bring these practices back. And it does not surprise me that health benefits accompany such fasts. And, of course, there are monetary benefits from eating less and abstaining from alcohol and other expensive beverages.

  • The Californian May 9, 2018, 1:50 pm

    A small eternity ago, I fasted for the first and last time. The first days were very hard, but in the end, it became a mental game to continue. I made it an entire 21 days without food, just drinking water. I lost about 23 lbs. and my body changed considerably.

  • Bryan June 3, 2021, 5:22 am

    This helped make the 36 hour fast before my colonoscopy a breeze. Although a headache filled one.


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