Carbohydrates….The Endurance Athlete’s Favorite Macronutrient

I have been doing quite a bit of reading about nutrition for endurance athletes and what it is that we really and truly need.  This investigation has been born out of the need to make sure that when I am racing 70.3 California that I am on my game and that nothing will stop me from succeeding at having the race I have been dreaming about.

As you may remember I wrote a post titled Nutritional Breakdown for Endurance Athletes.  In that post I suggested that the amount of calories from carbohydrates should be ~65%.  In doing further reading I am starting to believe that endurance athletes can get away with ~60% of their calories from carbohydrates.

Why are carbohydrates the largetst portion of calories?  It is because carbs are the preferred energy source for your body.  Your body’s cells are fueled by a digested carbohydrate (the process is called pyruvate.)  This process triggers a chain reaction (called the Krebs cycle) that uses calories for energy.  Our bodies do not store carbs readily; we use them and only small stores for emergency use.

As you can see the carb is the energy source for your training and racing.  The issue that I face is that I have a belief that I need to take in more than I actually need.  Our carb intake not only depends on the fact that I am swimming, running and biking daily but also on the amount of calories that I take in each day.  While I track my food, in that I write down each day what I have consumed, I do not track calories.  That being said it is almost impossible to deplete our carb storage with training, even a high-intensity session of 3 hours or less.  Or course you will still need to refuel during your training/racing but not to the extent that you may believe you have to. 

On Saturday I had a terrible run.  I spent all day after that run contemplating what went wrong.  I came to the conclusion that my error was really two errors.  The first was that I did not consume enough water prior to my training.  The second is that I did not have a good enough topping of my carb levels either.  These two combined to make the run the absolute worst run I have had in a year.  Since I was able to analyze what went wrong I woke up on Sunday and had a glass of water and a much smaller breakfast than I have been consuming.  I ate 1 teaspoon of sunflower butter on 1/2 a whole wheat thin with 1 teaspoon of dark chocolate chips and a 1/2 banana.  I drank water and no coffee.  I went to the pool and swam 3450y.  After that I went home and had essentially the same thing knowing that I had at least an hour prior to training.  I did have coffee but on the ride to the start of the bike I drank 20oz of water.  I rode for 3hours30minutes and ran 30minutes with no issues.  I felt fresh and restored my carb levels by consuming 223 calories per hour.  My run after being on the bike for so long was tremendous.  I ran 3.98 miles in30 minutes and felt stronger as the run went on.  My run from Saturday is a thing of the past, but I learned from it and will be applying those lessons going forward.

My new theory will be to eat slightly less before training in the morning and make sure that I consume those calories 1 hour prior to the training regardless of intensity.  I will also be sure to eat after my training but in less quantities.  We have all been at the end of a race and may or may not have felt famished but decided to eat the pizza, bagel, banana, nut bar, and everything else the race organizers were providing.  That is a waste of calories for you.  Be sure to get your carbs topped off but don’t go overboard.  The rule of thumb will be to consume 50% of your bodyweight in grams of carbs.

So what are good carbs?  We have all been told about pasta and breads and flour.  Don’t eat them they are not good for you….well how about  telling us what is good for us in terms of carbs.

Good carbs are found in fiber-rich and high-water content foods.  What would constitute those two attributes?  How about fruits and vegetables?  These foods will slow down the rate that your stomach empties and that will help you feel more content on less food.  The healthiest carbs to have before a race are fruits, vegetables and whole grains.

Here is a sample list of best-choice carbohydrates:

Fruits (approx. 60 calories per serving):  apple (small), orange, pear, nectarine, banana, peach and plum (medium sized), and many more.

Vegetables (approx. 25 calories per serving): raw vegetables (1 cup), cooked vegetables (1/2 cup), 1 whole green pepper, 7 stalks of Asparagus cooked or 14 raw, 1/3c of 100% tomatoe or vegetable juice,

Watch your portions because of calories: 1/3c of beans, 1/2c of corn, 1/2c peas or lentils

Carbohydrates are our friends as endurance athletes.  The idea or notion that we should eat a low or no carb diet is not a good idea.  Actually anything that limits your macronutrients (carbs, proteins, fats) is not a good idea.  We need all three but carbs are actually the most important because they will constitute the largest portion of your calories.

I will be discussing proteins and fats and their importance in future posts.  If you have questions before then do not hesitate to email me at

Sources include:  Wikipedia, The Runner’s Diet by Madelyn H. Fernstrom, Racing Weight by Matt Fitzgarald
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  1. Sounds like you have your calorie intake while racing dialed in. Being larger, I shoot for 300. Important not to “overload” while racing otherwise you will get an upset stomach (watch video of MACCA at IMWC 09, stomach cramps may be due to overloading). Next you need to dial in your electrolytes. A future post I am sure.
    Robert Shuler recently posted..ASK DR BOBMy Profile

  2. Great post! I meant to ask you last night, but do you want to do a guest post for me this week? I am going to work on mine today.
    Matt @ The Athlete’s Plate recently posted..Hummus Egg Salad with DillMy Profile

  3. lindsay says:

    i get ‘stressed’ out about the idea of calculating these things to a “t”. that’s sad, i know. (don’t tell my #1 fan)

    i know you don’t actually have to nail down a specific number – that’s just the mindset i get stuck in. and then i’m lazy about tracking/monitoring. i know! i’m horrible. basically this comment is just making me feel worse about my eating habits… i don’t treat myself like a “performance machine”. garbage in/garbage out.
    lindsay recently posted..dnfluMy Profile

  4. Nora says:

    I’m trying very hard to eat more fruits and veges as carbs. I spent most of my diet eating bread carbs with no room for much else. I still can’t get my weight to budge though.. :) So far I do feel better though!!
    Nora recently posted..Run- Wind and a PotMy Profile

    • Jason says:

      Check out how to get carbs at my Facebook page for the morning. You can find it here

      French Toast breakfast. The one without Cherimoya is about 420 calories and the one with the Cherimoya is about 650 calories. That cherimoya is loaded with calories but has 55g of carbs, 7g of fiber and 5g of protein. 1.9g of fat, no cholesterol and little sodium. It certainly makes you feel full.

  5. georgiasnail says:

    this post could not have come at a better time as I am really startinf to dial in my nutirition! Thanks J!
    georgiasnail recently posted..Burying The LeadMy Profile

  6. Kovas says:

    In the morning I find it easier just to skip fueling until after a run or cycle, works for me. Otherwise it’s just pure guesswork on my part.
    Kovas recently posted..Somnio Running Westridge Trail Shoe Product ReviewMy Profile

  7. Jon says:

    my favorite macronutrient is alcohol ;)p
    Jon recently posted..Records are meant to be brokenMy Profile

  8. Scott says:

    Great post, and you are so right about not needing to over carb for a workout, I have done alot of reading on this, and the problem endurance atheltes have is that they over eat for the training, Lets say they have a key 10 mile run or 3 hours bike ride, alot of atheltes will over eat for this training, having 2-3 cups of rice or pasta the night before and a large bfast, you dont need that many carbs to that work load. Ironman atheltes tend to gain weight while training for an Ironman, why? because they eat too many carbs for what the body needs, after the workout, the body uses what it needs for that particular workout and the rest of the calories just sit in your system.

    • Jason says:

      It was bad for me as I would consume so much after a workout regardless of 1 hour or 3 hours it was the same. It was nuts because I had a bloated feeling for hours afterwards and wasn’t really evaluating what went in.

  9. Jeff Irvin says:

    Good post Jason! Everyone’s body has different needs for racing and training and you are doing an excellent job of finding what works for you.

    When in the Build or Peak phases of training I try to maintain a 60% Carbs/20% Protein/20% Fat ratio. This gives me enough energy for heavy training and enough protein for recovery purposed. Sometimes if I am feeling fatigued I will up the protein intake.

    In Base training my ratio’s are 40%/40%/20%. When in maintenance and if I want to lean up I’ll drop the Carbs tp 20% and up Protein to 60% — this leans me up real quick – especially if I toss in some weight training!
    Jeff Irvin recently posted..And my Wolf Pack it grew by oneMy Profile

    • Jason says:

      You are absolutely correct in that everybody’s body is different and requires different things. I have been tweaking with my nutrition for about 3 months now especially after converting to a vegetarian. It is a lot of fun to find out what works and what doesn’t.

  10. MissZippy says:

    I agree with needing to top off your carb stores prior to workouts. However, I do think that we shouldn’t be so quick to label breads, etc. as bad. All depends on the type of bread. For instance, my favorite pre-run meal is a whole wheat waffle with some peanut butter (natural) on it. Gives me just what I need without too much fiber…I am one who cannot stomach fruits (other than bananas) right before a workout. It took me ages to get it figured out. Everyone is different in what they can tolerate and what works for them.
    MissZippy recently posted..Meet Dan and my winnerMy Profile

    • Jason says:

      You are correct in that it takes trial and error. I eat fiber before I race/train as well. I have 1/2 of a whole wheat thin bun and so far I have had no issues. I can eat a banana sliced on top of that too.

      Now I am going to attempt an orange prior and see how that reacts.

      The science experiment within your own body is a lot of fun to practice at.

  11. Marlene says:

    Thank you for this! I get carried away with the carbs very easily, which results in feeling heavy and bloated. Great tips/guidance here!
    Marlene recently posted..Week 6My Profile

  12. Jim says:

    Thanks for all of the research you do for all of us! I have really struggled with nutrition during this recent training cycle – but thanks to some of your ideas, I think I have them ironed out. Also, not enough water during the day tends to make me REALLY grawgy for my workout the next morning. Great post as always!

  13. Chris K says:

    Oh yeah, I am all to familiar with not fueling properly. For me, it’s what makes or breaks my race. For a race, I become mindful of nutrition and carb intake on that Monday. For a long run, more like on that Thursday. Doing it the night before is way too late.

    I also need to be better at eating more during my really long weeks.
    Chris K recently posted..Golf- Rock- and PopMy Profile

  14. Great post with lots of good info! I think nutrition is one of the biggest things that endurance athletes struggle with. In fact, I think it’s known as the 4th discipline in a tri!
    I really had to figure out what worked and didn’t work for me last year with my training. My stomach is pretty sensitive to eating certain foods, then exercising, so this year, with Ironman training, I’m really going to have to get it dialed in!
    Aimee (I Tri To Be Me) recently posted..A Big Mess!My Profile

  15. Jill says:

    Thanks, Jason! I know when I am marathon training, fueling properly with the right carbs makes a world of difference. Some days you cannot peel back the layers to figure out what went wrong, but most times you can and it’s such a boost emotionally!

    Do you use a specific program to help you track your carb/protein/fat intake? And curious, how much protein/day do you aim for? I took a class once from a big ultramarathoner who was a HUGE protein fanatic so I tend to lean towards more protein than carbs….but I am not a huge meat eater and struggle to get in about 100g w/o taking a protein shake (which I LOVE, but somedays I just don’t get to it).


  1. […] my focus on what goes into my system to allow me to perform at my best.  I have learned that the carbohydrates I consume are just as important as the protein and just as important as the fat.  I guess those […]

  2. […] my focus on what goes into my system to allow me to perform at my best.  I have learned that the carbohydrates I consume are just as important as the protein and just as important as the fat.  I guess those […]

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