Endurance Nutrition Overview

In my Week #3 post, I promised another post, and blog a bit on the topic of nutrition.


First of all, let me just say that we, as triathletes, tend to focus on swim, bike, and run.  That obviously makes sense, given the sport we’re devoted to, but I would argue that the disciplines we need to master so that we can excel are swim, bike, run, rest/recover, and eat.  Swimming, biking, and running are obvious.  Mastering the ability to rest and recover properly is not so easy, but just as important, and is a topic for a future post.  Eating…  now that is a complex topic.

Bottom line: food is fuel.  That being said, there’s no silver bullet with respect to endurance nutrition.  What works for one person may not work for another, but there are a few building blocks that are common for everyone.

The Science:  Where do we get the energy necessary to compete at the distances we do?  The energy comes from the synthesis of a molecule known as adenosine triphosphate (ATP).  I won’t get into the granular detail of glycolysis, the TCA Cycle or the Krebs Cycle, all of which you can research on your own, or I’m happy to show you where you can find info.  Suffice it to say that conversion of this molecule by mitochondria gives us energy.  When energy is used, the molecule loses a phosphate group, and become ADP (adenosine di-phosphate).


Basically, ATP is like a battery.  We draw on it for energy, and that converts it to ADP.  When we eat, food energy in the mitochondria converts it back into ATP, and we once again have energy available to swim, bike and run!  The trick, therefore, is to get the right food, in the right amounts, at the right time, to most effectively feed this process.

During exercise, the body uses primarily carbs and fat for energy purposes.  At low intensity, it’s normally fat that is used to meet the demands of creating ATP (although there is a little carb action going on).  At higher intensity, when you’re getting into zone 3 (or becoming more anaerobic), ATP synthesis demand increases, and fat can’t do the job on it’s own, so carbohydrate utilization increases.  Carbs require fewer “steps” to metabolize than fat, so it happens faster.  When intensity is low, fat has time to do the job.  When intensity is high, the faster synthesis that carbs provide is necessary to produce enough ATP to keep you going.  This is true even though, gram-for-gram, fat can produce far more ATP than carbohydrates.  It’s the speed…  at low intensity, people burn about 1-2g carbs/minute, whereas it can be upwards of 3g/minute while training at high intensity, or racing.  This is according to the lab tests done at Training Peaks.

Carbs get partially stored in the body as glycogen, which is the most readily available source of energy for ATP synthesis.  Most of this is in the muscles, with a little in the liver, and even less in the blood.  Unfortunately, these glycogen stores are typically somewhat small, but account for 80-85% (or more) of the energy we draw on while racing.  What happens when we run out?  The body uses protein and amino acids.  In other words, it starts eating muscle.  Dr. Iñigo San Millán refers to this as “eating itself to feed itself,” as yucky as that may sound…

In Practice:  So, we need to eat carbs, in the best manner to keep our glycogen stores full, and maintain ATP synthesis as we exercise.  The amount will be different for everyone, and will depend on size, activity level, and other factors.  Research shows that 30-60g/hour is sufficient for competition, usually, but for longer events (can you say Ironman?), especially those over 4 hours, 80-100g/hour is recommended.

Pre-workout and post-workout nutrition is critical to these concepts.  You want to have some gas in the tank before you get out there to do your thing, and you want to refill the tank when you’re done.  Again, pointing to the research, your post-workout meal should be between 3:1 and 4:1 ratio of carbs to protein.  You need the carbs to refill the glycogen stores, and you need the protein to start on muscle repair.  Beware the recovery drink that doesn’t have carbs (or is low-carb).  Massive protein intake without carbs doesn’t feed the machine effectively for endurance.  Also, it’s best to mix types of carbs (different glycemic indexes) to vary the rate of absorption.

What I do may not work for everyone, and we’ll be going off on a bunch of tangents if we get into the granular detail, so I’ll just state what I do, and why I do it, and let the discussion go where it may…

Pre-workout:  This depends on how much time I have prior to working out.  If I’m jumping right out of bed and headed to the gym (typically for a swim workout), I don’t eat any solid food at all.  I’ll take one gel (I use Hammer Gel) right before walking through the door to the pool.  Hammer Gel takes 15 minutes or so to get into your system fully.  That’s usually enough carbs to prevent a catabolic response (eating muscle), and Hammer Gel has amino acids.  Not all gels do.  Aminos can serve to improve focus during workouts.  For shorter workouts, I typically will have enough glycogen stores to get me through, regardless.

For running workouts, I’ll eat a banana if I’m short on time (pure carb), and knock back a gel, or if I have the luxury of an hour or two before working out, I’ll have some almond butter on an English muffin, sometimes with some jelly.  This gives me some longer lasting fuel at a variable absorption rate to help maintain my effort.

For cycling, I can manage more solid food, so I’ll have a double helping of oatmeal, with some brown sugar.  For protein, I’ll have some cottage cheese or greek yogurt.  Keep in mind that carbs and protein work together, and help each other synthesize.  Whenever possible, have both.

During the workout:  While swimming, I don’t usually eat J but if I’m doing a really long workout in the pool, I may have a bottle of Gatorade nearby to sip from occasionally.  These fast-acting carbs help ensure ATP synthesis.  For running, I rely exclusively on Hammer Gel and water.  I’m pretty resilient in most things, but I haven’t had much luck with other products while running, and have had GI issues.  Many people can tolerate more than me in this area.  For cycling, I like to have a Clif Bar with me, for longer rides, and Gu makes a great endurance gel called Roctane.  I’d only recommend using this for really long workouts.  It’s pretty potent.  I also use Skratch Labs in one of my water bottles, which helps with carb intake, as well as sodium/potassium.  All natural goodness!

Post-workout:  There are as many opinions on this topic as there are athletes out there.  I base mine on the science that I articulated above.  Get some protein and carbs into your system, in a 3:1-4:1 ratio.  And do it within about 30 minutes.  If you do this with liquid only, then follow it with some solid food within a couple of hours.  Good recovery options that hit these ratios include:

  • Chocolate milk (yum!) – just the right ratio of carbs and protein.  I get the Kirkland or Horizon single serving chocolate milk at Costco.  Perfectly convenient.
  • Greek yogurt with a healthy amount of granola – I go back and forth between Fage and Whole Foods 365 greek yogurt.  Both are really high in protein.  I prefer Udi’s Original granola.  Tastes great, gluten-free, all natural.  Good stuff.  To get the right ratio, I usually have to do one serving of yogurt to two servings of granola, and also have a can of V8 to get enough carbs and sodium.
  • Rice and beans –  I like brown rice or jasmine rice.  I mix the rice with black beans, and sometimes some chicken or tuna.  For more carbs, you can throw that into a tortilla and make a quick burrito.  This is also easy to pre-make before the workout, so when you’re done, all you have to do is pop it in the microwave for a little bit.

From a more general nutrition standpoint, some general guidelines include eating more meals every day (in smaller portions) to keep the metabolism going.  For most endurance athletes, 50-60% carbs is great, and the other 40-50% divided between protein and fat.  Don’t completely cut fat out of your diet.  As I said above fat is key to energy production.  It also protects organs and cell walls.  Another key point is to eat enough.  Heavily restricting calories is not conducive to endurance sports.  You’ll have a smaller gas tank if you do…   Also, don’t be shy about sodium.  Your body needs it to perform.

Finally, I wanted to stress the importance of hydration.  Hydrate well, and hydrate often.  As with carbs, your body uses fluid to perform ATP synthesis.  Fluid is the cooling mechanism for your body, and is used to eliminate waste.  Poor hydration can lead to many problems, so make hydration part of your daily routines, not just while exercising, but when you wake up, while you’re working, and every time you eat.  How much to drink while exercising/competing is a whole different topic, so I won’t get into that now.

In summary, I’ll state it once again: food is fuel.  Pay attention to what, how much, and when you eat.  To be serious as an endurance athlete, you need to do things intentionally, and food is no exception.  Make a plan, stick to the plan, and adjust as necessary.  We all learn new things every day, so try to evaluate what makes the most sense to change, if anything, and how often, by evaluating it against the science, and how you perform.  Some other basics include staying away from saturated fat, highly processed foods, and foods with high amounts of preservatives.  Some say that if it’s a type of food that never goes bad, don’t eat it, or if it has more than three or four ingredients that you can’t pronounce, don’t eat it.  Most of all, just use common sense.  Don’t deprive yourself of yummy things, just show some restraint.  With time, you’ll figure out what works for you personally, and you’ll see the effect on your performance.  Just make sure to start this significantly before race day, so you can be dialed in!

To keep myself accountable to my own advice, I’ll start including what I eat during my weekly posts.

Post any comments or questions you have, and I’ll be happy to get into more detail.  Until then, thanks for reading.

Train On!!


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