Thursday, June 23, 2011

Fasting for Running?

I recently started doing something that many would consider a bit odd if not down right nuts.  My fiance has called my crazy several times over the past month (more so than usual).  I recently read a post by Jason Robillard on Barefoot Running University (great site if you haven't been there yet) that really intrigued me.  Essentially in his post Jason talks about one of his training methods for the Western States 100.  Training for one of the most difficult and prestigious 100 mile race or any 100 mile race for that matter, can lead to some pretty unorthodox methods. During his training, Jason will not eat a significant amount of calories for a significant amount of time then he would run. The purpose is to run on depleted glycogen stores.  Often it would take runners of Jason's fitness level several hours to hit the "wall" or bonk but while fasting, he will hit the wall after only several miles.  The thought process is that you will become physically and mentally more prepared if and when the "wall" hits during a race. You will then have a better understanding of what hitting the "wall" feels like and some of the warning signs.  It may also lesson the severity of bonking.  Read Jason's post for more detail on his training. He does a much better job of explaining it than I.  I should point out that he has trained like this for other ultramarathons with success.

This made a lot of sense to me and therefore I went in search of fasting on the internet.  I came across a lot of info on fasting.  Fasting is practiced in many religions and in many cultures for various reasons all through out human history.  None of which really intrigued me or concerned me.  This is a running blog after all so I am much more concerned how fasting could help or hurt my running   I ended up coming across intermittent fasting or IF.  I found a website by Mike O'Donnell called The If Life. The IF Life gives some good background knowledge and some ideas on how to start intermittent fasting.  On his site is where I found the IF plan that I do now.  There are three IF "diets" he refers to.  There is the Warrior Diet, Leangains, and the Fast-5 Life.  I could have went with any but Fast-5 has a free e-book to download just for registering for a free account.  I read the book in a day and was fairly impressed.  Basically what Fast-5 calls for is 19 hours of fasting or not ingesting a single calorie and then you have a 5 hour window to eat.  For me this means I usually break my fast at around 4:30pm and won't eat anything after 9:30pm.  I then do the same thing the next day.  At first I found it pretty difficult.  I was the most hungry at times that I usually ate. For me it meant that at 6am and 12pm were the hardest times.  I combat this by drinking a lot of water and black coffee! I would also get very hungry starting around 3pm. However, over the next few days and weeks, the hunger dissipated.  I still get hungry but it is more something that is just there rather than something that bothers me or something that is always on my mind. 

The theory behind intermittent fasting makes sense to me as well. As someone with a Masters in Biology, anything that has roots in evolution I am very curious about (a bit different theory than the one on Jason's post).  Basically the theory behind IF is that for most of human history, we have not had access to an abundance of food.  We often had to go hours and maybe even days with out a significant source of calories.  Whats more is that we probably had to expel a significant amount of energy to gather or hunt those calories.  We couldn't just walk to the fridge and throw something in the microwave.  We couldn't pick up the phone and have pizza delivered to us that would feed an entire family.  We had to actually work, sweat, and yes even run to get our food.  Therefore it is reasonable to believe that our bodies evolved to function in a "fasted" state.  Our bodies may even function more efficiently in a fasted state.

I have actually enjoyed fasting much more than I thought I would and for different reasons than I thought.  I really was only doing it to experiment with my running and trying to become a more efficient runner. However, IF has actually simplified parts of my life. Which for me is always a good thing. Think about all the decisions in your day that are based on food.  For those of us that normally eat plain old cereal for breakfast, we have to decide which size bowl to use, which spoon, which cereal to poor, how much to poor, do you put anything on the cereal, how much milk do you poor, do you eat all of the cereal, do you drink the milk afterward, do you drink OJ and that is just for breakfast. We make most of these decisions with out giving them much thought but other decisions we agonize over. Often after making certain decisions we end up feeling guilty and then torture ourselves for eating the extra piece of pizza, or having and extra dessert or two.  Fasting during the day gets rid of those decisions and the guilt.  The only choice I make all day is not to eat.  I don't worry about what to have for breakfast or what to pack for lunch or if I'm going to order out for lunch.  I was shocked how much relief I got by eliminating these decisions from my life.  I just know that when I get home I get to eat pretty much whatever I want.  Intermittent fasting isn't about starving yourself.  I probably ingest close to the same amount of calories as I normally would.

There are many claims about the health benefits of IF.  These include reducing blood glucose, reducing insulin levels, weight loss, lowering blood pressure, and finally the potential to live longer.  All these benefits sound great and if intermittent fasting produces some of these results than great but as an avid runner I am not really concerned about weight loss or low blood pressure as they should all be taken care of by running 30+ miles a week. 

Now before everyone jumps at me, I too have heard that breakfast is the most important part of the day and that you need to east six meals a day to boost metabolism.  However, stop to consider where this information is coming from.  Then look in your cupboards at all the food we have.  Look at cereal, bagels, bread, oatmeal, fruit juice, milk and everything else we consume just for breakfast.  Then think about who would stand to lose a huge amount of money if we all stopped eating breakfast. Then think about everything we eat for lunch.  Food is constantly being thrown in front of us without us even realizing it.  What if western civilization only ate one large meal a day?  How much money would major food manufacturers, grocery stores, restaurants, fast food chains and countless other lose?  Then think about how much money you would save!  I understand that many people rely on jobs related to the food industry so there is never a simple answer but I believe there may be a healthier option.  Americans in particular just eat way too much food and way too much of the wrong kinds of food.  Maybe eating less often would be a good thing.  Maybe actually knowing what truly being hungry feels like would help us to know when we should eat not just because the clock says we should or because that is when society tells us we should eat.  I'm sure that many that read this blog will be a much more open minded.  As I am sure many of you are either veterinarian, vegan, or follow the paleo diet (would love to do this with my fasting), as these lifestyles seem much more common amongst the running community.  However, this IF is not for everyone and I am not telling you you need to do this but rather think about your eating habits and think about if eating differently could make you a healthier and happier person. 

As far as fasting and running.  I have yet to hit the "wall" while running.  This is probably because I have yet attempted a run over 4 miles in a fasted state but I plan to increase my mileage gradually. I do feel a bit more lethargic running after not eating all day but while I have no way of proving it, I believe that running in as fasted state will improve how efficiently my body can and dose use the energy it has available to it.  I am confident that when I do a longer run or race with full glycogen stores my body will process it in a much more efficient  manner and thus allow me to finish strong.  If it doesn't improve anything than I'm okay with that.  I really enjoy pushing my body to see what it can do.  So far, I have been very impressed with the limits of the human body.

Leave a comment below if you think I'm completely crazy or if you see the logic behind it.  Either way I am curious to hear what you have to say.


  1. I think your completely crazy, but I love you and your passion for running, and everything related to it! ;) your fiance

  2. I don't fast like that so much. But I do make sure I eat dinner by 6 and then run the next morning w/o eating/drinking anything but water most runs. I've done up to 10 miles like that. I've also done 4 hours of running/riding combo on 400/500 calories and bonked on the bike a few times. Not the same but when you bonk on the bike, it's still a slogfest.

  3. I think you may have inspired me to try this whole IF plan. I'm tired of counting calories. I run in the morning though, so I will have to figure out how much black coffee I am going to need :)

  4. Great post! I find it so interesting that even though we have all been taught the opposite of what intermittent fasting is, as soon as someone actually gives it a real try they suddenly have an appifany and say everything you just said in this post.

    Intermittent fasting opens our eyes to just how much we consume and how unnecessary it really is. It makes us feel better than we have ever felt and we start to question everything we have been taught. It makes us understand just how we have an obesity epidemic on our hands and frustrated that the answere is so simple yet so difficult at the same time because intermittent fasting is so different than what the diet and nutrition industries have been selling for so long.

    Keep questioning and keep discovering the truth and together with the rest of the IF community maybe we can start to make a difference and free people from obesity!

    Visit my blog for more info on IF. 19

  5. I do practice IF, however I would rather train to not hit the wall. One thought about running depleted is you can not truly train to your fullest. Thus you may be losing training and potential fitness.

  6. I tend to agree and that is why when I do my speed work and tempo runs that I don't do them is a fasted state.

  7. I IF for spiritual reasons. However I've noticed that on the days that I IF, my morning run times are greatly reduced and they feel a lot easier.

  8. Great article. I've been on IF for a month or so now for weight loss reasons, and I love how much more I appreciate my food. And the weight-loss is great!

  9. I have done many runs in a fasted state and I do notice that they are easier. In fact, when ever I eat, my runs always become a little bit harder. One day I fasted, I ran my max of 7 miles. I was dead beat, hips starting to have tiny pain, and legs were starting to give out (I stopped at that point.

    I usually just skip breakfast altogether, eat lunch, run 2 miles, and then a small dinner to make up (Still running a deficit calorie diet) and the results are AMAZING. More tone in my stomach (hips are starting to show, abs coming out) and people are noticing the weight loss. Call me crazy, but I love the results.

  10. Love your article!!! You and I may possibly be twins in how we think and our passion for running and life in general! I too am doing the fasting every day. I stop eating around 8pm and start back up again around 5pm. Giving myself just a 3 hour window to eat. I am very intrigued by how much my body is capable of and I too always love to push my bodies' limits. I am a gluten-free vegan and it is very hard to come up with meal ideas all the time. I have to admit fasting and eliminating 2 meals out of every day is just one great benefit! Dang, believe it or not, eating healthy vs. unhealthy is MUCH more expensive. :-) So cool to know there are others out there like me and my other half that are doing the IF way of life. We believe it is THE way to go for optimal health! You are definitely NOT crazy! :-P

  11. thanks for a super article Keep up the great search. I fast for health. The benefits are huge - spiritually I appreciate our Creator more and second I feel on top of the world. I cook my favorite foods for my men and have the will power to say no to the food for the love me. I feel like I am not addicted to food and intern free
    take care and good luck to everyone