On why you should fuel your races and workouts and practical tips to get started reaping those sweet sweet carb-enefits!
Recommended snack to accompany reading: Takis Blue Heat. Kill the whole bag, obviously.
And with this recommendation we firmly established a nice baseline of what comes to my mind today, when I read “eat like an athlete”. I gotta say my overall impression of the running community is that it’s giving more of a food-positive vibe. Pre-race pasta party, post-race celebratory pizza and the occasional gummy-worm after burger n fries. We burn a lot of calories and what joy it gives to compensate!
Although the pre-race pasta-party is not the best interpretation of a carb-loading protocol that suits you best, it still shows that the general concept is in many runners heads. While eating enough should be one of our top priorities all the time to ensure fast recovery and prevent injury risks that come along with low energy availability the idea of carb-loading is more of a performance driven one: Start your race with you liver and muscle glycogen stores as full as possible – allowing us to run in a higher gear for long with that sweet sweet sugar as fuel. High octane. Ho-ho-horse power!
Limits of topping up
Now unfortunately even if you were to combine Rigatoni and Farfalle with Spaghetti and Linguine you couldn’t trick your body. Your glycogen stores are gonna be filled to the brim and once the gun goes your world-class performance will siphon your stores faster than you’d like.
Not to worry though: Let’s just keep eating while running. Not too long ago you’d receive the recommendation to not surpass 60 grams of finest carbohydrates per hour. Shoot higher than that and you’ll not only leave a mark on the asphalt but maybe also in your briefs (or boxers, or g-string – you get the idea. Diarrhea. I’m talking diarrhea). That’s what people thought back then because thats about the maximum rate of glucose you can absorb in roughly that timeframe. But people back then were dull-witted! Of course you can also snack some fructose on the side and boom – Bob’s your uncle. You can shovel 90g/h in your face and race like Secretariat. Of course they weren’t dull-witted. Something something hairy shoulders of giants.
This is not big news. The 90g/h already is an established part of race-fueling guidelines and elite-level athletes from the domains of marathon, ultraendurance running and long-disctance triathlon have shared their intake of 120g/h and some went even beyond that (although with varying degrees of ‘being vomit-free’, a metric that I personally achieved to reduce drastically after my roaring twenties).
Bene bene bene fits
Performance. Ingesting carbs during your strenuous exercise will delay the metabolic crossover point simply meaning that you can cover your energetic needs from mainly carbs for longer. This again is beneficial because our bodies can gain more ATP (our bodies universal energy currency) per unit time than from fat. Although fat is more efficient in the sense that per litre 02 fat grants more ATP. In a study that measured elite marathoners during a 2 hour running protocol with different fueling strategies (60, 90 and 120g/h) the 90g/h condition delayed the crossover point relative to the 60g condition by about 40min and the 120g condition prevented the occurence of said crossover point.1
Economy. That exact same study also measured running economy which is expressed as the amount of oxygen you need per kg of bodyweight per kilometre. The lower the number the higher your running economy. With this marker Ravikanti et al. found a dose dependence as well: In relation to the 60g condition O2 cost was 3.6% lower in the 120g condition and 1.5% lower in the 90g condition. 1
Recovery. A field study accompanying a mountain marathon also had the three conditions 60, 90 and 120. They took a closer look at markers of muscle damage and lo and behold these markers measured 24h after the race were lowest in the high carb group. In addition to this runners in the 90 and 120 group also reported a lower perception of effort! 2
Bringing it all together
In short:
- running faster for longer
- while perceiving less effort
- moving more economically
- recovering better
Holy moly, that’s quite the package if I may say so! And you – yes YOU dear reader – are very likely not even hitting the the low-carb rates of 60g/h that served our bespoken studies as reference. This is some juicy and delicious and extremely low-hanging fruit. And just in case you haven’t done that mental leap yet: I’m not only talking races. What keeps us from fueling hard and long sessions as well? Just imagine the compounding effect of going a bit harder on your workouts and recovering better from them – day after day, week after week, month after month. This stacks!
Practical Takeaways
As I really hope that I managed to at least spark some interest in you and even the motivation to give this a try, here are some rapid fire notes that hopefully answer some common questions:
Which workouts to fuel? Harder sessions that exceed the 1 hour mark and long runs. Rough guideline, don’t overthink it – just experiment a little. Just today I ran some sub threshold Intervals that added up to about 55 minutes and I gulped two 40g gels. Just to give an Idea. I would advise against fueling every run. The carb need is just not there for a 5k Zone 1-2 jog.
Dosage start and progression? In case you never fueled during a session I’d start low at 30g/h. If you also never drink during your runs and you go the drink-mix route just the sensation of liquid in your stomach might take some getting used to it. If 30 works, ramp it up by 10g the next time.
Which form? From a physiology standpoint it does not seem to make any difference if you are ingesting via drink-mix, gel, chew or whatever.3 Apart from that I want to encourage you again to experiment. The cheapest and easiest option for ramping up the dosage is the DIY drink mix route. Buy some maltodextrin and fructose in bulk and mix them up in your sports bottle. You can experiment with ratios ( e.g. 2:1, 1:0,8) and you can easily serve yourself a 30g mix one week and a 38g the next if it pleases you. Of course you can also DIY the other forms – just be mindful that the extra effort does not introduce unnecessary stress. As you start to stomach more and more per hour the drink-mix route will become less feasable from my experience. I now rely on gels or combine gel and drink mix.
Pro Tip: Bring toilet paper!
References
[1] Ravikanti, S., Silang, K. G., Martyn, H. J., Johnson, K. O., Louis, J. B., Bampouras, T. M., Owens, D. J., Jones, A. M., Morton, J. P., & Pugh, J. N. (2025). 13 C-labelled glucose-fructose show greater exogenous and whole-body CHO oxidation and lower O2 cost of running at 120 versus 60 and 90 g·h−1 in elite male marathoners. Journal of Applied Physiology, 139(6), 1581–1595. https://doi.org/10.1152/japplphysiol.00665.2025
[2] Viribay, A., Arribalzaga, S., Mielgo-Ayuso, J., Castañeda-Babarro, A., Seco-Calvo, J., & Urdampilleta, A. (2020). Effects of 120 g/h of Carbohydrates Intake during a Mountain Marathon on Exercise-Induced Muscle Damage in Elite Runners. Nutrients, 12(5), 1367. https://doi.org/10.3390/nu12051367
[3] Hearris, M. A., Pugh, J. N., Langan-Evans, C., Mann, S. J., Burke, L., Stellingwerff, T., Gonzalez, J. T., & Morton, J. P. (2022). 13 C-glucose-fructose labeling reveals comparable exogenous CHO oxidation during exercise when consuming 120 g/h in fluid, gel, jelly chew, or coingestion. Journal of Applied Physiology, 132(6), 1394–1406. https://doi.org/10.1152/japplphysiol.00091.2022
Fast On Paper 