Taking carbs immediately before, or while running

(David Cooke) #1

Am I correct in saying that any glucose that I consume goes straight into the blood stream and from there directly to the muscles as an energy source when running?
I have been experimenting and my running form has improved immensely (10 - 12 K runs). I’m not talking about huge amounts of glucose, the electrolytes that I use contain a little glucose.

(Bob M) #2

I would say that if it works, and seems to be helpful, why not continue it?

I know that Zach Bitter (an ultra-marathoner) keeps keto mainly, but does use carbs during his races and many of his training runs. This is his website:

I don’t see there what he’s eating, though. He also has a podcast, called the Human Performance Outliers. Here’s one that might describe what he does (I have not listened to this one):

(GINA ) #3

I would expect so, it wouldn’t have the time or need to go into storage.

I usually train and run fairly low carb, but about 10 miles into a half once I was really dragging and figured I would try the sweet Gatorade they were offering at a water stop. I felt like Popeye after a can of spinach. It was crazy.


Direct to blood yes, but then your liver starts grabbing as much as it can, then your muscles start filling up. You get the energy for the run from it being in circulation not from being stored as glycogen, unless you’re running up hills or something.

It’s around the 20-30g mark where you start getting/feeling the energy from it. Below that it’s unlikely you’d notice.

(Kenny Croxdale) #5

Glucose Digestion Time

It is around 30 to 60 minutes, dependent on if it is a simple sugar or if take fasted or with a meal.

The downside of consuming glucose is that it dampens and resticts the body’s ability to access body fat for energy to some degree.

So, what’s the point.

Keto Adpated

Research by Phinney, demonstrated that Keto Adaped individual have virtually the same amount of muscle glycogen as individuals on a high carbohydrate.

In other word, IF you are Keto Adpated, you have more than enough muscle glycogen.

Kenny Croxdale

(David Cooke) #6

Thanks. Not being rude. But this does make a difference. (To me at least).

(Bob M) #7

While I think people can adjust to keto + running in terms of glycogen replacement, I wonder if there are other benefits for some carbs during running/riding/whatever? I know when I was keto and riding my racing bike, I mainly took just some water. But I ran out one time and bought a bottle of Gatorade or the like and felt great after drinking it.

I wonder if it acts on your brain and makes it easier there?

I also wonder how long a true transition to keto is? I am now at basically zero ketones (BHB) every morning, but it’s taken me 5+ years to get there. Maybe the transition to really being able to use free fatty acids (FFAs) and the like takes a long time?

And maybe even with that transition - however long it takes - some carbs might not be bad? When I exercise now, my blood sugar goes up. I assume that’s due to glycogen replacement or the like. It’s my body saying “I need blood sugar”. But I’m only exercising about 1 hour, and only 3 days/week.

What if I exercised 2, 3, 4+ hours? Could my body respond appropriately to that? Or would some carbs help?


According to what I’ve read, carbs help then, indeed. Just because my muscles have the same glycogen in and out of ketosis so I don’t need carbs for my short exercise, they run out if I keep my strenuous work. We can’t get huge amounts of energy from our fat reserves, there is a limit. So it makes sense even hardcore ketoers eat carbs when being very active.
It’s surely individual to some extent, maybe the body can used to being in ketosis even when running a lot, it would make sense to me…

But in the end, it doesn’t matter what is the theory. I am all for individual experimenting. If someone experiences carbs help, use them. I am open for that if I ever manage to be more active than what my body can handle using ketones with the actual food intake. I will notice and act accordingly. I don’t eat carbs by default just because I have a more active than usual day and it worked this far. But I am not very active and some hours of cycling and walking is fine even with elevation. Running is something I wish to do but can’t yet. I am curious what will happen when I will be able to run at least half a marathon (I expect I won’t need carbs but speed won’t be my priority, more like comfort and eventually doing it, using less time for that than walking).

(Kenny Croxdale) #9

Strenuous Work

That is a vague term with no meaning.

Muscle Glycogen

Some Muscle Glycogen is needed for during exercise. The extent of depletion is dependent on the intsntisy and duration.

With that said, Muscle Glycogen may drop but an indvidual rarely runs out of it.


Bonking in distances runner is when Muscle Glycogen primarily depleted, around the 18 mile mark.

Being Very Active

Another meaning less term with no definition.

Hard Core Ketoers

Most of them rarerly need carbohydrates. A well written exercise program ensure are able to use primarily use ketone for fuel with less glucose.

That is accomplished by maintaining an exercise program in either the Phosphagen or Oxidative Energy System. Information on this has been posted on this site.

A poor training program for Keto Adpated individual amount to using a crescent wrench to drive a nail instead of a hammer.

Kenny Croxdale

(David Cooke) #10

So Zach Bitter.100K and 24 hour champion is doing it wrong.
I have an 18K run tomorrow and will be taking carbs along with me, why? Because they definitely help. I was doing OK running without carbs, two years of that, and the one time I tried a half marathon with carbs (not carb loading) I got a startling PB.
One of the things I learnt about Keto is that it’s different pokes for different folks, I’m 73, I won’t have the same metabolism as a 20 year old and my dietary and fasting habits won’t be the same as other people’s. (18/6, 24 hour fast every two weeks, blood pressure and sugar normal).

(Kenny Croxdale) #11


That is an oversimplification.


To reiterate, Bonking usually occurs around the 18 mile mark.

Since Bitter is running a 100 K, the becomes a factor.

Bonking occurs due to glucose depletion.

Ketogenic Diet

Individual on a Ketogenic Diet still utilize glucogen to some degree.

However, what the Ketogenic Diet does is utilize ketone, while perserving glucose; glucose is spared.

Keto Adapted individual usuisaly are able to have more glucose in reserve, later in the event.

There are some Ultra Endurance Athletes on the Kegogenic Diet.

W\hy is working for them and not others?

With That In Mind…

  1. The intensity of the event over time contributes to when glucose depletion occurs.

That is one of the reason that Endurance Athelte respond well to a Ketogenic Diet.

The Lower Intensity of Endurace Events utilized the Oxidative Energy System; which is more effective at utilizing ketones; especially with a Ketogenic Diet. Research from Dr Stepthen Phinney M.D, PhD from the 1980’s has demonstrate that.

  1. One Time

…mean nothing, as you most likely know, when it come to reaseach or anything else.

The key is if the training effect can continutelly to be replicated over time.

Different Folks

Individual tend to believe they are “Snowflakes”, unique individual.

The reality is the we are more alike that disalike. That is why most medication, etc work for the majority of individual.

With that said, a small percentage fall into being “Non-Responder” and “Super Responder”.


Yes, there are differences with nutrition in regard to age.

Two of them are…

1) Pulse Feeding

Research show that older individual need to have a higher protein intake per meal that younger individual to achieve a similar response.

Older individual need double the amount of protein intake per meal than a younger individual

2) Protein Per Meal For Older Individuals

The amount of protein per meal for older individual needs to be around 40 gram of quality protein per meal/serving.

[quote=“cooked, post:10, topic:109426”]
my dietary and fasting habits won’t be the same as other people’s. . (18/6, 24 hour fast every two weeks, blood pressure and sugar normal).[/quote]

The Same or Similar

Actually, Intermittent Fasting (Blood Ketones and Breath Ketones), Blood Pressuer and Blood Glucose are going to be in the same range for older as with younger individual.

The exceptions are individual (regardless of age) that have some type of metabolic condition such as Diabetes or are genetically predisposted ot hypertension; meaning it is a gift from your parents.


  1. Bitter may need some gluclose during a 100 k Run to stave off Bonking, maybe not.

  2. With out knowing more about your diet and training, it hard to know what your doing or what might work for you.

  3. “Garbage In, Garbage Out”

One issue that ofen occurs is many individual (when it come to diet and exercise) incorrectly input the wrong data.

Raher than consider that they may have not correctly inputted the right training protocol or diet plan, they shiff the blame to the diet or training program.

Kenny Croxdale


Of course these aren’t fixed things, they are very individual too. We don’t live in a mathematical exact world, we don’t live in a world where we know everything and so on. We experiment and try to do what works for us. To me, strenuous work is especially vague as I never ever do that. But there may be a time when it will happen and if my body tells me I will need carbs, I will give it carbs and all will be well.
We don’t have a definition for “starving” either, for example, it still exist and important to avoid.
“Little enough carbs” has no definition but it’s what ketosis is about…

(Kenny Croxdale) #13


That is why there are guideline that provide acceptable ranges that to elicit the greatest effect

Incorrectly Applied

One of the issues trying to find out what works, is that many individual incorrectly apply the information in how to elicit the optimal effect.

That usually due occurs to a lack of knowledge in that area or misunderstanding of how to implement it.

"Research is what I am doing, when I don’t know what I am doing." Einstein

Einstein’s research on how light bends was initially incorrect. It took him two years to get it right.

Thus, no matter how smart an individual is, there are initial mistakes that take place in the learning process.

Phases That Have No Definition

Then why use Phases/Terms in which you have no concept of their meaning and no practical experience in?

Fat People

That is what Fat People use to determine if they need more carbohydrates or more food to eat; their body is telling them to eat more or it part of God Plan.


Acutally, there is a definition for it…

“Starvation is a severe deficiency in caloric [energy] intake, below the level needed to maintain an organism’s life. It is the most extreme form of [malnutrition].”

"Little Enough Carbs…"

That a great illustration of a meaningless, vague work combination of word with no meaning.

There are Guildelines on the percentages that need to be consumed to promote ketosis.

There are method of dermining if an individul in ketosis and how deeply with Blood Ketone Meter and Beath Betone Meters.

And this concludes this discussion on this topic. :slight_smile:

Kenny Croxdale


I don’t understand your style, it makes no sense to me most of the time. So I finish it here. I obviously will be me in the future as well as it works for some of us :slight_smile:

It has meaning. Little enough carbs means little enough carbs to be in ketosis for the person at some time. It’s even perfectly clear, it’s when ketosis happens. We just don’t have a number, we can’t. Humans don’t work like that. We all have some unknown number and it changes with time. It’s like our energy need. It’s a mystery though we often can guess it to some extent :slight_smile:
Not everyone has meters. I couldn’t care less about meters, actually. Even ketosis doesn’t interest me too much, I just want to feel RIGHT :smiley: You can’t even put numbers to feeling right but it’s still an existing thing! :smiley: And very important for me. Numbers aren’t.


I came across this again yesterday and found it fascinating. It is a short post by Peter Attia describing what happened to his BG, ketones and lactate during three types of exercise. He discusses glycogen, carbs, FFAs etc. He was using something called “Super Starch” midway through his cycling routine which added extra fuel but didn’t knock him out of ketosis - supposedly it doesn’t cause much insulin release.

I am finding moderate intensity cardio “burns off” my high fasting blood glucose while high intensity exercise (weights) cause me to make BG. I need to get a CGM to figure it out a bit better.

(Edith) #16

From what I understand, if you keep your endurance workouts in the low intensity range, below the lactate threshold, your body will spare the glycogen stores and run off of fat. It could be that you are working out above threshold and therefore need the carbs.

I’ve run for two hours and not needed carbs, but I kept my intensity low. One day I did my long run above threshold for most of the run. I needed carbs, particularly after my run. In fact, I was hungry all day long until I finally gave in and ate some starchy carbs. My body would not be satisfied until I ate those carbs. I have a feeling that Zach Bitter needs carbs just because of duration. If I recall from listening to some of his podcasts, he goes by percentages when his training level increases. If he eats 4000 calories, 25% of his calories from carbs, it is still a thousand calories of carbs. I don’t think he carb loads.

(Butter Withaspoon) #17

Thanks fitbod! That Peter Attia article/musings got better the further I read, inspiring consideration of my own experiences. Exercise biochemistry is fascinating!

For people who are not world class athletes, like me! The advice KCKO still works

(David Cooke) #18

"And this concludes this discussion on this topic. :slight_smile:

Kenny Croxdale"
If it does and you’re admin then I’ll leave the group. Not that you would care as you always seem to be correct about everything.

(Uwe F Herle) #19

I have also very low ketones after 2 years on Keto.
But is that a good thing?

(Bob M) #20

No one knows. My ketones are 0.1 or 0.2 mmol/l every morning, though they get higher during the day and if I fast longer than a day.