Running on fat


Hi all
Newbie here. Just to introduce myself. Been keto since beginning of the year and am training for multiple marathons in April. I think I’m probably fat adapted as I have just done an 18 mile run fasted. I’m assuming that as I seriously upped my running at the same time as starting keto that I fat adapted fairly quickly. I’m still wondering what to do about fuelling for the event but for the moment I’m just enjoying the ride.
I have read loads of the threads on this website and would like to say thanks for all the helpful info. Non low carbers don’t really understand this running lark without stuffing your face full of carbs:grinning:

(Full Metal KETO AF) #2

Multiple Marathons! Try here for like minded keto people.

(Robert C) #3

The two things I have heard (Dr. Bubb’s podcast) about this situation:

  1. You only might need to add the carbs if you are in a competitive (professionally competitive) situation. If you are just in it to finish or looking for PRs but are below competition levels (where they can take advantage of the carbs in a short window - a bit over 2 hour finish instead of 4 or 5 hours) then using carbs probably won’t help.
  2. If you do go the carb route you should include it in your training. For several weekends before the race, treat a long run as a race and add carbs. Experiment to get the performance you want. The point is to just avoid throwing a bunch of carbs down just pre-race as it can lead to pacing problems and maybe even stomach upset.

(Carl Keller) #4

Hello and welcome Amanda.

The top thread talks about what @Screenack ate, how he performed and how he felt afterward. You might find it useful.


Thanks for that. Have just read it. It’s always interesting the what the goody bag at the end has in it. I haven’t had gels for years or sports drinks. It’s amazing how people are still being told to carb up. I’m doing 10 marathons in 10 days and clearly want to make sure I’m actually eating enough those days. I’m not feeling the need to eat more at the moment just because I’m running but its obviously a lot more. And I’m definitely at the slow end, not professional!! Would really like to avoid stomach issues. I suspect they’ll all be over 5 hours.

(less is more, more or less) #6

I recall listening to a ketogenic-themed podcast by a person trying to run a marathon a day for a month, but gave up, due to health complications. Fancy that development.

This dude ran across Puerto Rico to raise money. Ketogenic Athlete has a lot of good material for athletes, so you should check out their podcasts:

I cannot find marathon-a-day for a month podcast, but I found this relevant article:


I’ll have a look at those. Thanks


So just did a half marathon this morning. Just my usual coffee. No breakfast, no water on the run and absolutely nothing from the goody bag at the end. Wasn’t trying to race but decided to put a little bit of extra effort in and ran faster than I have all year so pleased with that

(less is more, more or less) #9

So you scored negative splits? That’s fantastic!

I will say that I drank water frequently on my halfs. There’s some talk that we’ve taken the guidance to “drink a lot of water” too far, but, it seems to me that staying hydrated on a major effort remains important.


Fairly evenly paced throughout, so it was actually negative splits. Actually all my best races have been like that, keto or not. We have definitely been told to drink too much water over the years while running. Suffering hyponatraemia is more dangerous than being dehydrated but of course you’re right and we need to get the balance. I’ve run upto 18 miles without anything in a training run. Will definitely drink in my marathons and when the weather gets warmer.
Off out for another run now
Are you still running Screenack?

(less is more, more or less) #11

Sure am, I love / hate to run. I love the feeling when I’m running, and finished, but I dread it as I lace up my sneakers. I run three times a week, 2 6 miler’s and one 8 miler. I try to get in a 5 mile-ish walk as well. The walk, by design, is a pure act of pleasure, not training, other than we need “down days.”


Definitely a good feeling when you’ve finished :slight_smile:
Well, a fasted 20 mile run today. No food or water on the run but I definitely needed some water from about 15 miles onwards so will take a bottle on the next long one. The food didn’t bother me and as we were going out to lunch after and I had to get ready, I didn’t actually eat until about 3 hours later. My legs were tired though.

Anyone else out there still running on fat?

(Tamela Robinette) #13

I’ve been running mostly fasted but have a half coming up in a month and really should start experimenting with some fats on my long runs. My next long run is a 10 miler. Not even sure what to try except maybe nut butter. I don’t do peanut butter at all, mostly because I’ve heard it’s full of fungus because of the way they store them in bins full of moisture. What do you consume before or during long runs?


Hi Tamela - Yesterdays 20 mile run was done completely fasted. Just a black coffee before I left, so nothing since dinner the night before. I do all my runs fasted now. It depends what you want from your half and what stage you’re at. Have you been running/keto for long? Do you want to go out and race you’re half marathon or are you happy to just take it as another long run you’re experimenting with? A lot of people take nut butters with them or the other things I’ve heard of are apricots, raisons or macademia nuts. They won’t necessarily give you energy on the run (not enough time to digest and utilise) but I’m thinking also that perhaps during running we might sometimes on the longer ones just want some food as a pose to fuel if that makes sense.

(Tamela Robinette) #15

I’m just hoping not to bonk lol. I’ve been keto (this time) about 8 weeks. I’ve experimented with keto off and on a couple of years but want to make it a permanent lifestyle change as not to put the weight back on again. My last half was in October 2016 as a carb burner and it was pretty miserable but I finished in 2:19. I’d like to break 2 hours this time. This half is a lot flatter so fingers crossed but my speed just doesn’t seem to be there when I’m fasted on my training runs. Maybe it’s all in my head.


Sounds a little like me though I’ve never really had a weight problem. Taking 20 mins off is quite a lot. I’m about 8 weeks too and the speed is coming back albeit slowly. I’ve also massively upped my mileage so I suspect my legs are probably just too tired to go any quicker!! Just be a bit conservative on the day and don’t rush out really quick. Maybe get up early enough to have bacon and eggs or something for breakfast if you feel you want to. I wouldn’t have thought you’d need anything during the race itself. Just make sure you’re hydrated. Maybe take a bottle of water with your own homemade electrolytes in it. Let us know how it goes.

(Tamela Robinette) #17

Thank you! I will let you know. I really haven’t tried to push my pace too much maybe I’ll change my goal to 2:10 or 2:15. Thank you for the feedback, it eases my mind a lot!


So… Marathon number 1 of 10 tomorrow. Scary stuff. Will have scrambled egg and avocado for breakfast. Keto lunch when finished and I’m still not sure about during the race but will take a couple of nut butters and a couple of sausages. Am rather hoping to go without. Will drink water only but will take salt tabs with me. It’s day 100 of Keto though I’m not perfect:-/

(Tamela Robinette) #19

I have another half tomorrow. I did my half on March 24th in 2:10 so hoping to beat that. I ran it fasted but ended up having a snack size box of raisins at mile 7. You got this! Our bodies are remarkable and will get you through!


Good luck tomorrow Tamela. Let us know how it goes