Nutritional Breakdown for Endurance Athletes

We all know that our diets are going to be different than the average Joe.  This is because we are working hard to push our bodies and so we require different amounts of carbohydrates, proteins and fats.  Yes, endurance athletes need fat we just need good fat (well everybody should have good fat.)

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As a vegetarian I have to be creative with how I get the right amounts of these nutrients plus I have to be cognizant of calorie intake depending on intensity and length of workout.  It really is a science.  On days that I rest, which is always Friday, I do not need to take in as many calories as on a Sunday which is an epic training day that includes swimming, cycling and running.  Last Sunday I burned 3,851 calories and with a typical 2,000 calorie diet I can eat 5,851 calories to maintain my weight.  On a Friday my caloric intake should be about 2,000 to maintain my weight.  The math is quite simple in that if you burn 2,000 and eat 2,000 your weight will be the same.  Eat less calories and lose weight.  Eat more calories and gain weight.  Simple.

With all this dancing in my head and wanting to be at my ideal racing weight for Oceanside I decided to start tracking my food.  I eat healthy and have been able to lost 6 lbs since I switched over to a vegetarian diet back in December, but I wanted to make sure that this was true.  Funny thing about this is that tracking my food really opened up my eyes to what I actually put in my body.  Now, I have only been doing this for 2 days but just like tracking your training this tracking has held me accountable.  For example, the idea of eating an apple for an evening snack would have been easy for me to do, but last night I knew that I was coming up on my calorie limit and decided against it and drank 16oz of water instead and I felt full and no calories consumed.  I will say that Friday has always been my hardest diet day because I’m not training but my body is used to consuming calories that I continued to do this on Friday’s and when I wake up on Saturday I would find that I gained 1-2 lbs.  This morning there was no weight gain.

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I did some research on what an endurance athlete should have in terms of macronutrients.  Macronutrients are defined as being the classes of chemical compounds humans consume in the largest quantities and which provide bulk energy. These are protein, fat, and carbohydrate.

Athletes in general should eat a diet high in carbohydrates, moderate in protein, and low in fat. Another key nutrient that is a must for athletes is water.  We all know that we need to drink water for hydration but we sometimes forget to drink our water.  Rule of thumb for water is to drink half your body weight in oz.  For example, if you weight 150 lbs then you need to drink 750z of water throughout the day.

Why are carbohydrates important?
The body’s preferred fuel for endurance sports is muscle glycogen. Glycogen is the body’s storage form of carbohydrate. If muscle glycogen breakdown exceeds its replacement, glycogen stores become depleted. The result is fatigue and inability to maintain training and racing intensity.

How much carbohydrate should I be eating?
Carbohydrates should provide ~ 65% of total calories. To figure out the amount that’s right for you, multiply your weight in kilograms by 7, or multiply your weight in pounds by 3.2 – to give you the number of grams of carbohydrates you should consume per day.


Why is protein important?
Protein is needed for muscle growth and repair. Regular physical training tends to reduce muscle protein breakdown and protein loss from the body. While some protein breakdown may occur during exercise, protein build-up is enhanced during the recovery and the effectiveness of protein synthesis is increased. When muscle glycogen stores are high, protein contributes no more than 5% of the energy needed. However, when muscle glycogen stores are low, due to inadequate calorie and carbohydrate intake, protein is used for energy rather than for muscle growth and repair and may contribute as much as 10% of the energy needed for exercise. Such use of protein for fuel is expensive and inefficient.

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How much protein do I need to eat?
Endurance athletes need up to 50% more protein than sedentary adults. Protein should contribute ~15%-20% of total calories per day. To figure out the amount for you, multiply your weight in kilograms by 1.3, or multiply your weight in pounds by 0.6 to calculate the number of grams of protein you should consume per day.


Exercise does not completely eliminate the health dangers associated with eating a high-fat diet, such as increased risk of heart disease, stroke and certain cancers.

How much fat can I eat?
Endurance athletes as well as all people should consume less than 30% of total calories from fat and less than 10% from saturated fat.

Packed with my new knowledge I wanted to see how my first day, which happened to be a rest day, came out in terms of the macronutrients.  On Friday I consumed 2,439 calories and my breakdown was 65.22% Carbs, 11.02% Protein, 23.76% Fat.  I was a little light on the protein side but I did not train so I think I was right where I need to be.

Today I have consumed 1,040 calories (as of 12:50p) and burned 1,494 calories.  This leaves me with approximately 2,889 calories based on a 2,446 caloried diet.  My breakdown so far is 56% carbs, 17.5% protein and 26.5% fat.  The fat can be attributed to the fact that I consumed 3 tbs of peanut butter already today.  Up for lunch is some quinoa chili topped with an egg substitute scramble.  This should help me with my protein and carbs and lower the fat since the only true source of fat will be the 1tbs of olive oil used to cook the chili.

Do you track your food?  Are you monitoring your macronutrients?


* Each source I read gave me ranges of the % of macronutrients and so I essentially averaged it out to come up with these numbers.  If you are a registered dietitian please comment and update us endurance athletes on what is essential for our diet.  Sources included,, and others.
** I use to track my calories and macronutrients.
*** I am not a registered dietitian and these rules of thumb are based on my research.  If you have questions please contact your Dr to make sure that you are getting a professional’s opinion on what your body should be consuming.
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  1. MissZippy says:

    I figured out a long time ago that eating with roughly those balances of proteins, carbs and fat work for me. I learned how to do it and now can do it w/o having to track. I suppose everyone can benefit with more detailed tracking, I just know I only have so much time/energy to devote to it, so I go with my rough balances. I’ve also started reading Phil Maffetone’s latest book, which has SO much information on all this…you might find it of interest given your deep interest in nutrition.
    MissZippy recently posted..What IfMy Profile

  2. Mandy says:

    I don’t have a lot of energy to devote to tracking what I eat. I try to eat good food, non-processed, mostly plants. LOVE the look of the blog BTW Jason…it is rocking!

    • Jason says:

      It is not easy to do for sure. I actually bought a day planner that is just for tracking meals and when I get home I input it all. I know I eat healthy but as a new vegetarian I want to make sure my recovery proteins are where they need to be.

      TY for the compliment on the new look of the site. Need to fill in that grey area as it looks broken up like that.

      • Mandy says:

        I think the best way to keep track of everything is to do what you are doing with the planner. I should start doing that just to keep track of my intake and see where I am getting calories that I don’t want/need.

        The site looks great. Not sure what grey area you are talking about, but really, this is awesome.
        Mandy recently posted..Baxter Trip ReportMy Profile

  3. Marlene says:

    This post is super helpful! Thanks for all the great info. I recently started traxcking my food in order to lean out to a better racing weight, but I also want to make sure I am fueling myself properly. It’s a thin line!
    Marlene recently posted..Three Things ThursdayMy Profile

  4. I’ve used training peaks for several months now, and I know if I keep my intake around 1800 or less calories a day, I will lose weight over time. Been at 1800 and vegetarian since october, lost 30 lbs.
    Carolina John recently posted..Transvestites have the best cupcakesMy Profile

  5. Jen says:

    Great info, Jason – while I try to track what I eat – I more importantly try to eat as “cleanly” and healthfully as possible.
    Jen recently posted..Five unexpected things that Im enjoying now that Im thinnerMy Profile

  6. Holleigh says:

    I second what Jen just posted. I tend to be so obsessive when I track what I eat. I try to eat as clean and vegetarian as much as possible so I do not feel the need to track. I love the info in this post as always!!

  7. katie says:

    what a great, informative post. i track calories roughly, but am pretty good about tracking protein because i find that’s where i lack if i don’t. thanks for this one, it gets a lot of wheels turning!

  8. Terri says:

    You know, when I’m working hard if I’m not getting about 70 grams of protein a day I am starving. This is more than I should need, by the numbers, but I guess part of it is finding what works for you. Another great post!
    Terri recently posted..Turning a CornerMy Profile

  9. This is great info. and a nice review for me heading into my training schedule. I don’t really track what I eat, but have thought about doing it, especially this year with IMAZ training. I’ve tried to do it in the past, but it was sooo time consuming! I just need to find something quick, easy, and simple and I’ll be good to go!
    Aimee (I Tri To Be Me) recently posted..A week in review and other things tooMy Profile

    • Jason says:

      I told Mandy that I bought a planner that is used just for that then the next morning or at the end of the night I put it all in and do a quick analysis. Since you are eating healthy already you probably don’t have to make a lot of adjustments and this might be the best way to do it for you as well.

      I put in yesterday’s lunch through dinner and this morning’s breakfast into in 35 minutes and it’s done. I will write down the rest of the day and put it in tomorrow.

      Hope that helps.

  10. Jon says:

    Great post Jason, however I disagree with eating less on an off day. Just because I am doing not as much exercise on an off day, doesn’t mean I am not going to need that energy for the upcoming weekend. I think eating less the day before the weekend is not a good idea. I don’t want to have to fuel my body entirely that morning or during the workout to get through it, then have to worry about recovering for the next day. I’d rather keep my base caloric intake steady every day rather than have large peaks and valleys. Just wait till you start getting closer to race day, your body will tell you when it needs fuel, and its going to be often and every day regardless of how much work you put in.
    Jon recently posted..NYRR Gridiron Classic 4 Miler Race Reportand other stories of painMy Profile

    • Jason says:

      Jon – As always thanks for the advice. You have been awesome thru this journey. My point was that consuming 4k calories on a day with no training doesn’t make sense to me. During a ride I am consuming about 1100 calories plus my regular caloric intake of 2400 and so taking in 3500 calories on a day with no training seems counter -productive.

      Do you have articles I can read about nutrition on a rest day?

  11. Kevin says:

    Tracking food is as important (if not even more so) than tracking your training. You could easily blow through hundreds of calories without giving it a second thought if you don’t track it. I also use, and I love the tool (along with the iPhone app). It’s helped me lose 30 lbs last year.

    If you’re trying to lose weight, I think that the most important thing to remember is to try and eat smaller meals more often, which helps to stimulate your metabolism. Most restaurant portions are much larger than what a body needs, so take half of the food home and eat 2-3 hours later. Most experts agree that weight loss is 85% nutrition and 15% exercise, so start tracking your food! Great post Jason.


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