I’m very excited to have Laura from Mommy Run Fast over her posting today, especially since she’s writing on a topic of big interest to me–glycogen depletion long runs. I’ve done two of these so far in this training cycle and I’ll fill you in on that in another post. For now, let’s let Laura explain the thinking behind them:
Hi everyone! I’m Laura, from Mommy Run Fast. I’m happy to chat with you all today while Miss Zippy unplugs. I always appreciate the good discussions over here.
I read an intriguing article recently about proper fueling for endurance workouts and I would love to hear your thoughts. The authors argue that athletes can enhance their performance in a workout (or race) by allowing 3 hours between the time they eat and the time they begin their workout.
The theory is that by waiting a full 3 hours, your body will have completed the digestion process and can pull from your energy stores more slowly and evenly. In contrast, if you eat an hour or two before your workout, your body will still be digesting your food which will elevate your blood sugar, causing you to delete your muscle glycogen stores too quickly.
Elevated blood sugar results in insulin release, which can lead to hypoglycemia. High insulin will also reduce the fat-to-fuel conversion rate and your body will metabolize carbs at a much faster rate than is optimal.
I don’t know about you, but I often wake up hungry and can’t fathom doing a 90 minute-plus workout without fueling first. However, the article insists that if you are refueling properly after each workout (complex carbs + protein), your muscles will be well-fueled even if you’re stomach is telling you you’re hungry. If you don’t have the time to wait 3 hours before a long run or bike ride, they recommend starting on an empty stomach and beginning to fuel soon after your workout starts.
For shorter workouts (under 90 minutes) eating an hour or two before is fine and actually beneficial to your workout. You will be drawing from your glycogen stores very quickly, but will not deplete the stores.
Although it sounds counterintuitive, the authors insist that the three-hour rule makes sense from a physiological standpoint. I haven’t experimented with it yet, but am curious to see if I will notice a difference in my energy levels and overall performance.
What are your initial reactions? Any marathoners or triathletes who have tried this fueling strategy?