Fueling Training and Racing–Thoughts?

Fueling during the marathon is something I really want to figure out for future races. In training I rarely take anything before or during workouts. At most I will take in some caffeine and electrolytes.  I rarely ever hit a wall or slow down in training. The interesting part is that if I do eat a meal (even 3-4 hours) before a long workout I almost always end up slowing or having to put in more effort over the last 3rd of the workout. I would not call it “bonking”, but there is a noticeable slow down and increase in effort….this does not happen if I do the workout fasted from the night before. Heck, I’ve had some of my greatest workouts ever (and yes, they are long…over 22-24 miles) with only taking in electrolytes (S-Caps).

After doing a ton of research on the topic I am wondering if I might have a little bit of reactive hypoglycemia.  It is my experience in the marathon that really leads me to the reactive hypoglycemia diagnosis. Once I start taking gels or drinking Gatorade I notice the spike in blood sugar as I get lightheaded and even dizzy sometimes. If I don’t maintain the fuel (sugar) intake every 10-20 minutes I crash too much and end up slowing or putting in much more effort to maintain my current pace. Another interesting thing I have noticed over the past few marathons is that once I do start taking in fuel during the race I find myself slowing. For example, I may go from running 5:20s to feeling like it takes the same effort to run 5:35-40/mile. This has happened in every marathon I have done. I have not actually “hit the wall” or “bonked” since my first marathon, but I do end up slowing down significantly over the last 3rd of the race. I do not think it is a coincidence that the time of slowing down coincides with the 5-15 minutes after I start taking in fuel. I have experimented and started taking fuel at 3 miles, 6 miles, and even half way. Every single time the pace/effort goes within 5-15 minutes of taking in the sugar.

What am I going to do about this? First, I am going to try a diet higher in fats and lower in carbohydrates. I’m not talking about taking out carbohydrates completely, but I will definitely limit the amount I am taking in on a daily basis. The biggest things I am going to work on taking out are sugar and refined/processed carbohydrates. It is not going to be easy as I have a sweet tooth. Also, when I mention higher percentage of fats I am talking about more “good fats” (coconut oil, olive oil, fish, chicken, nuts, almond/cashew butter, avocados, etc…). My diet is going to consist of good fats/proteins, lots of vegetables and a limited amount of fruits (berries and apples as they are lower in fructose). Before you jump and say it’s not possible or unhealthy I urge you to do some research. I have been doing quite a bit of research on the topic and there is a ton of legit information out there. I’ve also been reading a bunch of information written by Professor Tim Noakes on the subject. I even had the honor of tweeting back and forth with him about the topic.

In the future I am not going to eat anything before a race of half marathon or shorter (I actually had my best half marathon ever last Spring without eating a thing beforehand….but I did start taking a sip of gatorade every 2 miles starting at 6 miles). For the marathon I am probably going to wait until much later in the race to fuel (if I fuel at all). I will still take in water/electrolytes.

I will try and keep updating my progress both with training and diet.

I would love to hear what other people have to say about this……


1 thought on “Fueling Training and Racing–Thoughts?

  1. Ryan McGrath

    Dave – rather than try and self-diagnose what’s going on, I really think you owe it to yourself to discuss with professional. You train and compete at a professional level, and if you don’t feel the workouts are your limiter, nutrition very well could be.

    I’m sure I’m leaving minutes on the table due to my diet, which is admittedly terrible.

    I’d suggest talking to two people: Melissa Majumdar, who is a Registered Dietitian and can probably provide some better insight on your day-to-day eating; and Brian Shea, who owns Personal Best Nutrition (personalbestnutrition.com). He consults with some of the top Ironman professionals on their race day nutrition.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s