🥖 The Case for Increasing Your Carbs

I have been training for The Grand Traverse 27-mile trail run, which, even though I’m a longtime endurance athlete, is a stretch goal for me, since I’m a cyclist who likes to run and not a runner primarily. When I’m not training for something like this, my long runs generally clock around 7 or 8 miles. The past few weeks they’ve been 18 to 20.

So, I’ve also been trying to get on board with the increased carbohydrate intake train and get more carbs throughout my runs. One, so my gut is trained, and two, to see if I perform and recover better. I’ve always had a bit of a fickle gut, so for most of my training/racing life, I’ve pretty much stuck to 30 to 60ish grams of carbs (~120 to 240 calories) an hour. I’ve been trying to get about 30 grams every 20 to 25 minutes, mostly through a variety of gels, because I really hate chews (not that I love gels…). 

It’s been imperfect. I’m not fully emptying each gel packet, so I know there are some carbs left in my vest’s trash pocket. I am also sometimes in a tricky section of trail when it’s time to fuel, so I wait till I’m on safer ground. All this is pretty common, as research shows there’s a pretty big gap between what folks say they’re going to consume and what they do. I do try to fill that gap when I hit a refuel spot where I actually stop and refill my water flasks, which gives me the chance to also scarf down a bit of bagel, cookie, or some other treat.

As imperfect as it is (I’m probably hitting 75 grams an hour all said and done), this process is definitely working. My heart rate and perceived effort stay pretty consistent throughout the runs. I haven’t bonked or gotten vapory from running low on fuel. Maybe the best part: I definitely feel like I recover faster. Sure, the stairs feel a bit steep the rest of the day, but the next day I feel pretty good and my next run–generally two days later–feels great.

I’m also keen to see if I can raise the ceiling a bit, which just several years ago, I never thought I’d be typing. For decades, the sports nutrition gospel capped carb intake at 90 grams per hour during long runs and races. Now, that’s the floor for some athletes who are routinely pushing 120 grams or more.

Though there’s a lot of debate over carbohydrate intake and endurance exercise online, most of the current research does seem to point to moving the upper limit into the triple digits, and for the first time, scientists also have some female-specific data on the subject. 

A major review out earlier this year in the Journal of Nutrition revisited over a century of carbohydrate research and concluded the upper limit should likely move from 90 to 120 g/h, at least for trained athletes, because both gut absorption and whole-body carb burning keep climbing at that higher dose. But almost all of that evidence came from men.

Researchers from Liverpool John Moores University, England Athletics, and Science in Sport stepped in to fill that gap and tested eight elite female marathoners at 60, 90, and 120 g/h during two-hour, near-race-pace treadmill runs. The results, yet unpublished in a journal, mirrored the men's data: at 120 g/h, women burned more of the carbs they consumed, stayed carb-fueled instead of drifting into fat-burning, and ran about 2 to 3% more efficiently, according to a Runner’s World interview with the researcher. (Also worth noting that SiS funded and sells the products used in this research, but I still appreciate a study on women specifically.)

That said, both males and females are more likely to have GI distress when they’re pushing those limits, with females reporting more gut-related symptoms. So, approach with care–and plenty of practice–if you have any desire to go that high. For myself? I’m going to try to nudge it up just a bit to see if I can hit closer to that 90 mark over the next couple of months. Stay tuned for what happens next.