Hi Kate,

Others in this group can speak to this more precisely than I can, and I’m not currently a runner, but from what I have read, it can take your body up to 4-6 weeks to fully adapt to burning fat instead of glucose. If I’m not mistaken, this is the time it takes for your mitochondria to adjust.

Stephen Phinney has done research on low carb athletes and their performance—you can like find some threads about that in the “low carb topics” sticky post (or just start with the launch pad). Don’t forget, electrolytes, particularly magnesium and sodium, need daily replenishment on LC.

Sounds like the 10k is far enough away that you might well be fully adapted by then. Consider toting along either some coconut water or a keto electrolyte replacement cocktail, to prevent “bonking”.

Congrats on your success thus far, and best wishes for getting back to your stride with running soon!

Mary

I agree that sodium is probably your main problem. You may feel a slight dip in energy while getting fat adapted but it is usually quite slight. If you feel noticeably slower, fatigued, brain fogged, headachy or have muscle aches, that is most likely caused by not replacing lost sodium that went away with your lost water weight.

Most low careers need at least 3000-5000 mg of sodium a day. For reference, there is 2300 mg of sodium in a teaspoon of table salt.

If I start having problems during a workout, I put the salt under my tongue...it should absorb pretty instantly that way, and it doesn't taste quite as strong.

velocitykate wrote: »

I am a runner. Not a fast runner and I definitely have problems with motivation when It's wet or cold. But I run.

3 weeks ago I started a low carb diet and have so far lost 3.5 kg (around about 8lb). I am very pleased by this and will definitely continue as I still have more weight to lose and this is the only diet I've tried when I'm not continually hungey.

But running is a struggle - I suppose I must be hitting a bit of a mini wall each time I run because my body wants to burn carbs and there aren't any. I feel like I am running through treacle, and I am even slower than I was before.

Is this something which is likely to improve as my body gets used to this new woe? Or will I always feel like I'm running through treacle?

I have a 10k coming up at the end of March. Should I just go back to eating carbs for a few days before it, or should my body get used to this - many thanks for any advice

It will improve and evwntually one day it will nir be there but it could take a lot longer than you might have expected.

Been there. Done that. Still learning. I base my experience on running, published research not gurus web celebrities fads or eminent experts plus extensive experience with science based sports coaching pedagogy.

Allowing for huge individual variability and without knowing your personal variables, my perception from actual experience and from observations is that training adaptation to endurance based running while keto adapted takes a lot longer than it takes simply to adapt to keto nutrition for daily living.
Having considered hundreds if not thousands of published papers relevant to this, this topic is very sparsely dealt with. Yes a few can be named but there's actually a huge gap overall. This is promising since thus means there is a lot more to be explored in a scientific manner.

I disgress above to highlight the point that there is little reliable and established published science to guide you. So most of what you see on blogs and in posts (including this post) and hear is hypothesis. If someone is also selling you a product or a service, caveat emptor.

Briefly, for you to consider from my n=1:
Pre keto+ insulin dependency -> could hardly walk up a steep hill.

Keto + insulin dependency -> could potter up and down hills for 2 or more hours, without any running training. Difference could only be attributable to keto adaptation. Learnt to experiment with exogenous salt prior to starting.

Keto + insulin dependency + training from the beginning -> now actually running non stop at pace up and down hills. Essential point is that I restarted training as though i had never before. Or, put another way, I hypothesised that the entire physiological system for running at pace needed to be re-engineered from "ground up".
It is working for me.

You might not have my insulin dependency challenge, but perhaps it only shows more acutely (a) keto works for endurance based running and (b) it requires comprehensive retraining of the entire system needed for running.

That is, just keto adaptation alone is insufficient and also don't assume you can just continue running as for pre-keto without training on keto adaptation.

How long will that take? That's a huge question.

No published papers address that. Looking to raw science in cell metabolism and lots of other physiological systems, I guestimate it will take at least 6 months for substantial and sustained adaptation to keto adapted high paced running and up to 18 months to be optimally adapted.

6 weeks is too soon to expect not to have the heavy treacle experience while running at higher pace.

A silver lining is that tou can use this time to build up functional strength for your running.
This will improve your performance, reduce injuries and improve your lifetime health.

Since you indicate you are more of a light recreational runner (and that's great), consider adding a short session somewher sometine doing something strenthy that you like.
Even walking up a steep hill would be OK.

I started 5 weeks ago and just started feeling normal this week during runs. Before that, I hit a wall at mile 2 and was running at least a minute slower per mile than usual. I agree with adding salt but mainly it’s a waiting game. As soon as the other Keto flu type symptoms were completely gone, my regular running endurance returned.

Tagging @blambo61 as this recent discussion may be of interest to him as a runner.

2 things I've learned running on low carb:

1. During the adaptation period (first 8 weeks of low carb), it is important to stay at lower exertion in order to improve adaptation and to prevent bonking.
2. Make sure to get electrolytes.

*A 3rd thing is that a lot of fat adapted runners do supplement carbs during high exertion events (such as races).

The standard dieter (high carbs) can't oxidize fat in skeletal muscles beyond about 55% of VO2 Max, and 65% for elite athletes. The whole point of fat adaptation is to improve this level, and exercising at too high of an intensity during the adaptation period harms this effort.

As to the 10K at the end of this race, you need to choose between these 2 things:
1. Go slow, as though it is a training run, and accept that you are not going to have a PR. I.e. Run it and don't race it.
2. Take some carbs that you can tolerate 30 min. before the race. This is only if you can stand it without GI issues. It's only a 10K, so I would not exceed 50g (probably better at 30g). An idea to avoid much GI distress is hard candy, as that will go into your blood through the surface of your gums and inside of cheeks rather than through your stomach.

Running_and_Coffee wrote: »

midwesterner85 wrote: »

2 things I've learned running on low carb:

1. During the adaptation period (first 8 weeks of low carb), it is important to stay at lower exertion in order to improve adaptation and to prevent bonking.
2. Make sure to get electrolytes.

*A 3rd thing is that a lot of fat adapted runners do supplement carbs during high exertion events (such as races).

The standard dieter (high carbs) can't oxidize fat in skeletal muscles beyond about 55% of VO2 Max, and 65% for elite athletes. The whole point of fat adaptation is to improve this level, and exercising at too high of an intensity during the adaptation period harms this effort.

As to the 10K at the end of this race, you need to choose between these 2 things:
1. Go slow, as though it is a training run, and accept that you are not going to have a PR. I.e. Run it and don't race it.
2. Take some carbs that you can tolerate 30 min. before the race. This is only if you can stand it without GI issues. It's only a 10K, so I would not exceed 50g (probably better at 30g). An idea to avoid much GI distress is hard candy, as that will go into your blood through the surface of your gums and inside of cheeks rather than through your stomach.

This seems like great advice. With that in mind, would you advise against running a half marathon at week 7 of fat adaption, even at a really slow pace? (Frequently ran them before doing Keto, and am "trained up" in terms of mileage.)

I think that would be fine.

midwesterner85 wrote: »

2 things I've learned running on low carb:

1. During the adaptation period (first 8 weeks of low carb), it is important to stay at lower exertion in order to improve adaptation and to prevent bonking.
2. Make sure to get electrolytes.

*A 3rd thing is that a lot of fat adapted runners do supplement carbs during high exertion events (such as races).

The standard dieter (high carbs) can't oxidize fat in skeletal muscles beyond about 55% of VO2 Max, and 65% for elite athletes. The whole point of fat adaptation is to improve this level, and exercising at too high of an intensity during the adaptation period harms this effort.

As to the 10K at the end of this race, you need to choose between these 2 things:
1. Go slow, as though it is a training run, and accept that you are not going to have a PR. I.e. Run it and don't race it.
2. Take some carbs that you can tolerate 30 min. before the race. This is only if you can stand it without GI issues. It's only a 10K, so I would not exceed 50g (probably better at 30g). An idea to avoid much GI distress is hard candy, as that will go into your blood through the surface of your gums and inside of cheeks rather than through your stomach.

I've found the UCAN superstarch is great for right before a run but is very expensive. For me, I would use before a race but not for regular runs. Regular corn starch seems to work just as well for me and it is much cheaper and those things do not upset my stomach even during a race.

I've got a friend that has eaten keto-style for a couple of years and does bicycle racing. I talked him into trying the UCAN starch and sold him on it not spiking insulin much and he tried it and reported back that he had an exceptional race with it and was very impressed with it.

midwesterner85 wrote: »

blambo61 wrote: »

midwesterner85 wrote: »

2 things I've learned running on low carb:

1. During the adaptation period (first 8 weeks of low carb), it is important to stay at lower exertion in order to improve adaptation and to prevent bonking.
2. Make sure to get electrolytes.

*A 3rd thing is that a lot of fat adapted runners do supplement carbs during high exertion events (such as races).

The standard dieter (high carbs) can't oxidize fat in skeletal muscles beyond about 55% of VO2 Max, and 65% for elite athletes. The whole point of fat adaptation is to improve this level, and exercising at too high of an intensity during the adaptation period harms this effort.

As to the 10K at the end of this race, you need to choose between these 2 things:
1. Go slow, as though it is a training run, and accept that you are not going to have a PR. I.e. Run it and don't race it.
2. Take some carbs that you can tolerate 30 min. before the race. This is only if you can stand it without GI issues. It's only a 10K, so I would not exceed 50g (probably better at 30g). An idea to avoid much GI distress is hard candy, as that will go into your blood through the surface of your gums and inside of cheeks rather than through your stomach.

I've found the UCAN superstarch is great for right before a run but is very expensive. For me, I would use before a race but not for regular runs. Regular corn starch seems to work just as well for me and it is much cheaper and those things do not upset my stomach even during a race.

I've got a friend that has eaten keto-style for a couple of years and does bicycle racing. I talked him into trying the UCAN starch and sold him on it not spiking insulin much and he tried it and reported back that he had an exceptional race with it and was very impressed with it.

A lot of fat adapted athletes use that. As a type 1, I've had problems in the past during high intensity runs (races). So I've decided to give UCAN a try this year. Soon, I'll experiment with some training runs and decide if it is a good idea during a race.

ETA: I'm not sure it would be very valuable for a short race like a 10K.

I use it or regular corn starch to run after a 19-20 hr fast so I can do it. Or I will use coconut oil or both. I'm not type 1 or 2.