Running on Fat

In conjunction with my current marathon training plan, I will be upping my keto game.  For several years I have followed a fairly low carb high fat (LCHF) or ketogenic or modified Adkins regimen.  This lifestyle has helped me maintain a target body weight, completely restructure my training nutrition, and (I believe) improve other life aspects like immune system, skin complexion, and energy levels throughout the day.

Before making the transition, I had always focused on eating low-fat foods to keep from gaining weight and high carb foods for running fuel. I had no data to support this behavior. This was just common practice in the running community and in our society. (The same society with ever-increasing rates of obesity, heart disease, and pharmaceutical usage.)  I also believed that by simply training for my next marathon, I would achieve my weight loss goals.  This is all too common.  I would bet the majority of non-runners begin a training program in order to lose weight and get in shape.  But by race day, there’s a good chance that they may have actually gained weight.

So, I, like so many, would eat my pasta the night before long runs, consume gels every 45 minutes on runs, and chug sports drinks throughout the days to stay hydrated.  Also, as my mileage increased, so too would my appetite / capacity.  My meal portions seemed to grow and I would snack more throughout the day.  Hey, I was burning more calories running, right?  Well, sometimes not enough to offset all those gels and sports drinks.  In addition, I could never find the perfect combination of the right gels and / or sports drinks.  I probably tried them all.  Many would either give me a boost and crash effect, or upset stomach, or bloating, or nausea, or just general discomfort.  These issues did not present with every run or with every type / brand of fuel.  However the inconsistency was more concerning.  It meant that when I did experience GI issues, I also would also have mental issues to sort out.  It would really mess up my training, or worse, race performance.  My fueling strategy began dominating my training plan and my conditioning approach.  You aren’t supposed to spend months training for a marathon just to figure out what you will eat along the way.

My experiences led me to start to ask questions.  Was I not carbo-loading enough before my long runs? Was I not consuming enough during my runs?  How could the marathon boom of the 1980s have happened before all these highly specialized gels and sports drinks were available?  My dad ran some marathons in his day with just water.  Why doesn’t that work today?  What if there was another way?

Eventually, I found a book called “The Art and Science of Low Carbohydrate Performance” by Phinney and Volek.  That book and many after changed my training and my life.  Check out my book list to find other great resources on low carb living and training.  They do a much better job of explaining the science behind low carbohydrate or ketogenic eating.  Basically, your body can utilize glucose or fat generated ketones as a source of fuel.  Glucose is produced from the consumption of carbohydrates.  Ketones are produced from fats when the body can’t rely on glucose.  So that’s the difference, glucose is the first source your body tries to utilize for energy promotion.  Glucose is much easier to access but is less efficient and harder to store.  Fat is harder for the body to access, but is comparatively limitless.  You just have to train the body to utilize fat effectively.  A quick “keto explain” search on youtube will provide a much better understanding, as well.

The only way to train the body to utilize fat is to deplete your carb stores through exercise.  In the absence of gels or sports drinks, a traditional runner depletes all the available carb stores in the first two or three hours of aerobic activity.  Without replenishing those carbs, the body will switch into fat-burning mode.  However, without practice, the body is less effective while in fat-burning mode.  I believe the runners of today, with all the gels and quick carb fuels, rarely deplete their carb stores and therefore don’t train in the fat burning mode.  The only time I would get into the fat burning mode would be on race day, when I would push my body past its normal operating condition, but wouldn’t replenish my carb stores soon enough.  The runners of yesteryear would practice this cycle over and over again.  They would experience the shift in fuel source on most long runs and be able to practice in that fat burning mode.  They would become more efficient at utilizing fat and would be prepared for the switch on race day.

I could have just quit using the carb based fuels and gone old school.  That may have worked.  However, I wanted to test the concepts in the books and make a drastic change in my eating plan.  I wouldn’t call it a diet because I really wasn’t trying to lose weight and I didn’t view it as temporary.  These books also outlined the effects of insulin on fat storage which was very compelling, as well.

I decided to switch to a low carbohydrate high fat based lifestyle in July 2013.  There is an adjustment period and eating low carb is not without a commitment in order to utilize fat as your primary fuel.  If you consume too many grams of carbohydrates while in fat burning mode, your body could go into storage mode and not switch back to fat burning mode for a couple of days.  The books helped me understand that my fitness level and performance would suffer initially, like a few months, and then would rebound.  I think many people who try this give up too soon and claim this eating style is unsustainable.  The basic transition, based on my personal experience after dropping the carbs, went like this:

  • Sluggish, foggy, and irritable (3 days) – search “keto flu”
  • Gimme sugar, gimme sugar, gimme sugar (5 days)
  • Sudden and frequent bathroom stops required (10 days) as your body sheds water weight
  • Drop in body weight (~10 lbs), mainly water weight (the same 10 days)
  • Stopped getting hungry before standard meal times (after 2 weeks)
  • Reduction in the urge to snack (after 3 weeks)
  • Elimination of the afternoon slump (after 3 weeks)
  • Significant reduction in training fitness and endurance (1-2 months)
  • Return to baseline fitness and endurance (3-4 months after)
  • Gains in fitness and endurance (4-6 months after)
  • Reduction in soreness and inflammation (4-6 months after) thus improved recovery after workouts
  • Eventually, only need minimal water on long runs.  No breakfast, no gels, no sports drinks, no hassle
  • Stopped getting hungry; could eat when I wanted or not

As you can see, this took time.  I tried to recoup what I could of my marathon training to participate in a September race, which wasn’t great.  However, by November, I was able to compete in a 6-hour endurance race and won with 35 miles.  That’s right, I ran the longest distance in my life and all I consumed was some bacon before and some nuts and water during.  The old me would have fretted over having enough gels (10?) and ounces of fluid (72 – 90?) on hand.  I would have also gone through the over-caffeinated sugar rush and crash several times that day, which would have killed my focus on taking and keeping the lead.

Since becoming fat adapted, I have still had some bad performances, but I have also had some good ones.  I don’t think a low carb lifestyle is a magic bullet or a secret weapon.  I view it as a means to reduce another variable to deal with in training – what to eat during a workout or race – nothing.  Now, if I have a bad day, I know it is because I went out too hard or I didn’t train enough hills or I let my head get to me.  It won’t be because I had a stomach ache or I couldn’t drink enough at the aid stations.

One side effect I have experienced since making the change is weight loss.  I lost about 15 pounds and have kept it off with no real effort.  Also, it may be correlative, but I have been able to reduce my training significantly.  I have trained for marathons with one or two runs per week.  These aren’t personal bests, but still respectable finishes.  And I could still walk the next day.  Basically, once I hit that breakthrough where I noticed my performance returning, I was sold.  Even after some poor showings in races, I was convinced that my days of gels and sports drinks were done.  Much more than just being a better runner, I was resilient.  I could do a hard workout and feel little or no soreness the next day.  This meant I could make every workout count.  That’s what you want, right – purposeful workouts in your training plan?  I now have the ultimate flexibility and freedom in my training, which, for me, has been worth it.

If you are currently running on fat, have tried it in the past, or even if you don’t believe in it, please leave a comment.  I would love to hear from you or answer any questions.