Foods before and in a 30k trail running event?


I have a 30k trail event in 3 weeks time. It’s a fast event (except for the sandy beaches) south of Sydney. I have been on reduced carbs for a month, and on a full on Keto diet for a week (feeling good). I train at a low intensity, but can run fast in events (at a cost latter). This even is one of 2 Alpha events on my annual calendar where I really put the hammer down. So I am keen to get a good time in this event, rather than just go along for the ride.

My questions for this are:
1/ If I was going to take on board some carb fuels for the event (it will mostly be anaerobic), then what fuels should I consider if I have been mostly keto for the preceeding month ?
2/ Pre event fuelling, should I up the carbs the night before, or early on the day before the event ? If so again, what sort, complex or simple carbs. I would be inclined to do complex.

I will try to do some 20k runs before the event with some fuel experiments, but as there will be only 2-3 of those I need to narrow down the options :slight_smile:

For a longer event, eg: the UTA 50k then I would probably lean more towards keto like fuels with some carbs as a back up. The UTA will be in May 2022, so there will be more time to adapt and experiment.
Note - trail running is not as steady state as road running, so there will be anerobic section on the uphills /.

PS: I dont eat gels, really dislike them. In the past if I need carbs in a fast event, then I used " Fruit Salad Soft Jellies" a lolly from Woolies or Coles, mostly sugar and glucose. Once I start eating the carbs, then I pop them one at a time like clockwork every 15-20min. In very long events 50-100k, I like slabs of cheese in a SD baguette or chibatta, soaked with olive oil (been doing that long before I even heard of Keto).

I have perused the web for ideas and have listened to many Zach Bitter podcasts, etc. But most of the carb suggestions are delivered in a liquid form. I have evolved my event nutrition to the point where I drink mineral water/electrolyte and eat carbs seperately, that way I can better manage the body demands & only have the calories when I need them.

Thanks :slight_smile:

(Robin) #2

Good luck with your run. Hopefully someone on here will have answers specific to your situation.

(Butter Withaspoon) #3

I’ll try… Since you’ve only been low carb for a month, and this is an A race, I’d transition carbs back up before the race. I wouldn’t stay keto from now until few days before. A great time to do a very keto metabolic reset is for the few weeks after the race.
I’m not competitive/fast so I don’t have personal experience to give you of exactly this. But from what I understand, eat good amount of slow carbs the night before- it might be 100 or 150g but I’m guessing here. If it’s unprocessed and well below the crazy 300 and above, I hope you’ll be good. Don’t eat to the carb snoozy feeling!

In the morning I would tend not to eat carbs before the race, but trickle them in during. Maybe cold boiled potatoes washed down with electrolyte drinks. This would be my first choice. Cashews presoaked in cold water might work. Cold porridge could work. I never feel like sweetness helps, and often it upsets the gut.

If I think of anything else I’ll add it. Good luck!! What sort of time and which event are you doing?

(Butter Withaspoon) #4

When I say slow carbs, I mean complex carbs.

If you always eat before long runs and races maybe you should at this point in adaptation. It’s hard to say.

If you’re going to be running at intensity above that crossover point where glucose becomes the main fuel, maybe it’s better to think of this one as a carb fueled race. The advantage for you is you may have begun to nudge the crossover point to a higher intensity, but there would be much more progress after 6 months of keto/low carb. So maybe you can still use those sugar jellies, just don’t start them before the race and plan on using fewer.

If you haven’t watched Jeff Volek, the Faster study on YouTube then do it! Zac Bitter was in the study.


Thanks Hallie, great advice !
The event is the Coastal Classic - Otford to Bundeena.
I will go into carb periodisation from Sat (2 weeks to the event) for at least a week as next week will have higher intensity training sessions. I have only run at a low intensity through the short reset period that I am currently doing.
After the event then I will go for a full reset. In Feb we are in a 102km trail event in NZ and that will be a good test of the keto approach, it will be a focus on finishing rather than competing, so can let the fat burning process determin the pace :slight_smile:
Taking on some of your advice, at the moment the plan is: to have a not too big, starchy carb meal the night before the 30k. On the morning of the event will aim for a shake with MCT oil in it. Then once the even starts wait 30 min before fuelling (wont be a chance until then in any case). Zach Bitter mentioned that he starts in event fule 30-60 min in, being a short event 30 would be prudent as the intensity is higher.
As for what to consume in the event, that is the still pending question that needs some more research.

(Butter Withaspoon) #6

This is awesome! And exciting! I’ll reply more later. I hope you’ll keep us updated with experiments, thoughts and progress.


With a week to go to the 30k event, the question of what to consume in the event remains. I have been perusing the web and research papers looking for answers. So far I am inclined to go for a fast absorbing form of Carb, preferably not fructose (so as to not switch off the fat burning). Choices are straight glucose &/or maltodextrin. I can make a product for the event to try, just need to decide on the main ingredients. In a longer event I might try Kumera or complex carbs, but the 30k is fast paced and does not have any easy sections for recovery (& digestion).

Any suggestions appreciated :slight_smile:

(Butter Withaspoon) #8

Maltodextrin sounds like a good idea, as does avoiding all fructose. If you’re a fast runner some commercial product is probably a good idea.
I’m a cold potato eater (soaked with salted butter ) so I have no experience to offer.

(Bob M) #9

Listen to Zach Bitter, who discusses what he eats for long runs.

For instance, I thought this was very interesting (and I don’t run, at least right now):

He eats a keto/low carb diet, but does use carbs during (and possibly around) races. He recommends not changing things too much before a race. If you have raced before and know something works, use that.

So, if there is something you’ve used in the past that worked, use that. If you want to use maltodextrin (which I also used to use for biking), I’d test that out first. But with only a week to go, I’m not sure how much testing you can get in.


We tried eating rice for two dinners before some harder workouts, that was the first time I had really had carbs in over 2 weeks. It worked, definitely a energy and performance boost. Now a few days after that experiment, I still feel like the energy levels are higher even though I am on strict Keto. Thats interesting ?

I had delved into the Zach Bitter podacsts, very good and he is one of the few athletes to really detail the carb periodisation. Episode 262 I listened to a week or more ago,podcast on the run :slight_smile: Excellent info.

Next will be the in event nutrition, no time to test that as I am in a taper and dont plan to do much this week. I will go for 2 fuel sources, one will be glucose based, the other sweet potato, if one feels good then I can focus on that. Will avoid fructose, though may carry one packet of Blocks for emergency use.


cycling rather than running, but I find that old school carb loading (depletion before carbs) works for me. Just eating carbs before without depletion doesn’t do anything except make me feel sluggish and kick me out of ketosis. During events I eat a dried plum about every 20 minutes. Half a butternut squash in eveing meal after the event. For general exercise, no carbs though.

(BuckRimfire) #13

Advice for long-term planning, not this race, but Jeff Volek seems to think that it takes more than a few weeks to prepare yourself for keto performance. People on low-carb in the FASTER study have high ability to burn fats, relative to traditional expectations*, and they had been on low-carb diets for many months prior to the study.

*and relative to the control group, but I think they should not have fed different pre-exercise shakes to the control and low-carb group. While it makes sense that someone would want their “pre-race,” or in this case, pre-experiment meal to be the sort of thing they normally eat, I think the results would be easier to interpret if they had either done the exercise test after an overnight fast, or everyone had been given a low-carb shake. The way they did it, how do we know that the differential effect of the two groups was not due to an acute insulin effect in the people who had a high-carb shake immediately before the test?

(BuckRimfire) #14

Link to the FASTER study:

(Bob M) #15

I would guess that wouldn’t be the case, only because these were highly trained athletes, who have a very good and low insulin response anyway.

Edit: Meant to say, it could be a factor, but it’s unclear how much. So few of these studies are done with long-term low carb/keto people.

(Butter Withaspoon) #16

Update? How did you go in your race?