Advanced Stuff: Fueling for Endurance Sports

I’ve been working hard on the subject of “fueling for endurance” over the last few months, and after reading lots of studies, and talking to lots of runners, and experimenting quite a bit on my longer runs. In doing so, I think I’ve come up with the perfect formula for “fueling while running”.. (Perfect for me, anyway, but it should apply fairly well across most endurance athletes).

Apologies in advance that this isn’t necessarily weight loss related, and MOST people trying to lose weight aren’t out running half marathons, full marathons, or doing 100-mile bike rides. If you’re not an aspiring endurance athlete, this probably won’t be that interesting.  I decided to write it down more for future reference to myself, and figured there are probably others who might benefit at some point.

Who should worry about fueling like this?

Anyone doing “endurance” sports. Marathon / half-marathon runners, triathletes, long distance cyclists, or anyone else doing anything that requires more than about 90 minutes of continuous, vigorous effort.

What happens if you don’t fuel properly?

Improper fueling during a long run causes all kinds of problems, the most common are:

  • Muscle cramps
  • Severe dehydration
  • “Bonking” (running out of energy before the race is over),
  • Water retention after the run is over (yeah, you can gain 5+ lbs on the scale the next day if you’ve got this wrong).
  • Blacking out
  • Feeling lightheaded or nauseous

Replenishing Electrolytes

Do this every 60 minutes (AND right as you’re starting out!!).

Remember, when you run, you sweat, and your body is pushing these critical items out in your sweat. You have to put them back!

  • 800mg sodium
  • 400mg potassium
  • 200mg magnesium
  • 200mg calcium

Fortunately, there are pills you can use that will handle this for you.  Example Amazon purchase is here. (4 pills will fill out the above ratios). So in this example, you’d take 4 of those pills before you start, and then 4 more every hour during your activity.

Refueling with Carbs

You should also eat ~50g or quick-hit high-energy carbs every hour (break into 15 minute increments to keep the fuel constant).  You want the BAD kind of carbs. Sugar is great, in this case! (And might be the ONLY time when sugar is actually beneficial to the human body!)

Here’s an example of how you might run a 15m carb fueling rotation (this schedule assumes you’re running roughly a 9 to 10 minutes mile).

  • Miles 2,10,18 – Eat 7 sour patch kids
  • Miles 4,12,20 – Drink 6.5oz of Gatorade Frost (The full-sugar stuff!)
  • Miles 6,14,22 – Eat a Gu Roctane Gel Pack
  • Miles 8,16,24 – Drink 6oz of water

Use the EXACT same fueling schedule for a half-marathon as for a marathon. You shouldn’t need to do any real fueling for a 10k or 5k, other than possibly carb-loading before the race (personal preference).

When I have this dialed in right… I feel like I can run forever!