Ketones, carbs, and physical performance.

Or more specifically, ketone monoesters and carbs.  Literally, this study was a high-dose ketone monoester supp sans caloric or carb restriction.  I know, weird right?


Ketone ester


Non sequiter nutrition notes, #context, etc.:

1) ketone esters =/= ketone salts.  Ketone salts are either sodium or potassium-dominant.  Ketone esters are essentially salt-free.  Possibly helpful background reading here.

2) nutritional ketosis =/= starvation ketosis =/= ketone supp ketosis.  Because #context.

Starvation ketosis, but not nutritional ketosis, is muscle-sparing.  Ketone supps sans carb restriction might be.

3) the theory of ketone supps for sport is: 1) ketones are an energetically favorable fuel; and 2) they’ll spare glycogen, theoretically allowing prolonged duration of moderate-to-high intensity performance.  Adding in carbs will likely further this.

4) I have no studies to support this, but the idea of ketone supps in the #context of high carb doesn’t sit will with me.  Seems like high levels of both substrates = mitochondrial overload and oxidative stress.  Maybe.

5) there’s a gradient of fuel use during exercise:

-explosive power: creatine, anaerobic

-high intensity: glycogen, anaerobic

-low intensity: fatty acid oxidation, aerobic

But it’s a gradient with a lot of overlap, and ketoadaptation further blurs the lines.




divide and conquer

n=6, male endurance athletes

Ketone monoester supplementation led to a pretty high level of ketones (45g dose = 6mM!), and exercise drained them:


blood ketones


The reason you see the lines plateau and not decline (as if the ketones were continually being oxidized) is because they’re still being absorbed from the gut, and they are continually being oxidized.  Absorption and/or production minus clearance = “metabolic flux.”

At higher workloads, ketone oxidation declined as a percentage of total fuel oxidation, but total ketone oxidation increased (leading to lower blood levels) because total energy expenditure is elevated:


ketone oxidation


“Estimated d-BHB oxidation during steady state exercise increased from 0.35 g/min at 40% WMax to 0.5 g/min at 75% intensity.”



Part 2. Exercise study comparing fat to carb to ketone monoester

Here’s where the lines begin to blur, ie, where it gets interesting:


plasma lactate


Exercising at a relatively high intensity is going to use a lot of carb, which produces lactate, and slugging down some butter isn’t going to change this (compare carb [open diamonds] and fat [yellow squares])… in contrast to ketoadaption, or in this case, ketone monoester (blue circles).  Ketone supps make anaerobic work appear more aerobic; in other words, ketones allow you to burn fewer carbs at the same relative intensity.

If you interested in this kind of stuff, Nanci Guest and Tim Noakes have been debating it relentlessly on Twitter lately.


Moving on, ketones blunt lipolysis, even more so than carb:


lipolysis ffa glycerol


…NOT because insulin:




Part 3. Cool study: dissociating effects of ketone receptor activation and ketosis.

Nicotinic acid activates the ketone receptor, which inhibits lipolysis. Inhibition of lipolysis increases, whereas ketones decrease, the reliance on glycogen during exercise; ergo, highest lactate with nicotinic acid and lowest with ketones, reflecting highest and lowest carb burning:


nicotinic acid


As expected and mentioned above in the “non sequiter nutrition notes,” ketones suppress glycogen use during exercise.  In the figure below, dark staining reflects muscle glycogen:




Part 4. Physical performance study

1 hour cycling at 75% max (glycogen-depleting), followed by 30 minute all-out sprint for distance.

Carb group made it 20.1 kilometers vs. carb + ketone group made it 20.5 km.  2% further (P<0.05 haha).



Ketone monoesters are ridiculously expensive, so no-go for weekend warriors or recreational athletes.  If you’re literally going for a Gold Medal, then a 2% improvement might make a difference.

Alternatively [theoretically], a carb-adapted metabolism might do just as well with a ketone boost as a ketoadapted metabolism would do with a carb boost (this appears to be how some of the elite “n=1” LC athletes do it).  But still, it’s like 100x less expensive to be ketoadapted & have some carbs than be carb-adapted and take ketone monoesters.  So, unless there’s a Gold Medal on the line or you have a money tree… ymmv.

So, throwing some ketone monoesters into your pre-workout drink might improve net physical performance, depending on your sport.  But then there’s that other issue, that elevated ketones and glucose = no bueno.  Acute physical performance boost at the expense of healthspan?  Idk.

For full access to all articles and much more (or if you just like what I do and want to support it), become a Patron! It’s three bucks a month and there are many other options. Sign up soon because there are only a limited number of spots left at the $3 level. It’s ad-free and you can cancel if it sucks ????

Also, I’m open to suggestions, so please don’t hesitate to leave a comment or contact me directly at

Affiliate discounts: if you’re still looking for a pair of hot blue blockers, Carbonshade  is offering 15% off with the coupon code LAGAKOS and Spectra479 is offering 15% off HERETrueDark is running a pretty big sale HEREIf you have no idea what I’m talking about, read this then this.

20% off some delish stocks and broths from Kettle and Fire HERE

If you want the benefits of  ‘shrooms but don’t like eating them, Real Mushrooms makes great extracts. 10% off with coupon code LAGAKOS.

calories proper


Become a Patron!





Be Sociable, Share!
  • Tuck

    “I have no studies to support this, but the idea of ketone supps in the #context of high carb doesn’t sit will with me.”

    Yes, 100%. Perhaps there’s some reason the body doesn’t do this on its own?

    Seems a bit faddish. Perhaps for a short-term performance boost, but how long until this is classified as doping?

    • TechnoTriticale

      re: …how long until this is classified as doping?

      Can it even be tested for, vs. endogenous ketones in an athlete on a deep KD?

      Another concern is that the two MLMs hawking EKs (Exogenous Ketones) in the US are doing so with some emphasis on weight loss – albeit in the context, for at least one of them, of a low carb diet. Aside from which did what if weight is lost, there will be people doing EKs on SAD, and probably not losing weight. It won’t take much excuse, or many adverse reactions (if any) for the FDA to step in and “help” us…

      …which could be tragic for people who might desperately need EKs – those with responsive neurological ailments, those doing R-KD cancer therapy, those doing extended fasting for various reasons, or merely those temporarily easing keto flu or wheat withdrawal (assuming EKs actually help in those two scenarios).

      If Navy SEALs have indeed been using EKs to ward off oxygen toxicity (and apparently not in the context of a full-time KD), ONR probably knows quite a bit about long-term use.

      • EKs for weight loss?

        I doubt it, given the lack of association between endogenous ketones and weight loss. Also, the added EKs shut down lipolysis.

        eg, see study by Coleman

        • TechnoTriticale

          re: EKs for weight loss? I doubt it…

          Oh, I concur. Dom has even said so, and during an MLM conference call with the enrolled resellers listening (????).

          It might favorably affect appetite.

          • “It might favorably affect appetite.”

            if so, then weight loss wouldn’t be off the table …but I still doubt it 🙂

      • Tuck

        “Can it even be tested for, vs. endogenous ketones in an athlete on a deep KD?”

        I wouldn’t be surprised. These are not the same chemicals as the endogenous ketones, and may well leave a marker.

        “f Navy SEALs have indeed been using EKs to ward off oxygen toxicity (and apparently not in the context of a full-time KD), ONR probably knows quite a bit about long-term use.”

        Dominic D’Agostino is the guy who’s been doing the research on this. He’s done several very long podcast interviews that you might look up. The Naval research he’s been doing is very preliminary, so no, they don’t have experience with long-term use yet.

        • Tuck

          BTW, my definition of “long-term” for something like this is a couple of generations. So I’ll continue to get mine the old-fashioned way for the next 40 years or so…

          Tinkering with systems we don’t understand is what got us into this health mess in the US in the first place…

  • Effect of beta-hydroxybutyrate on whole-body leucine kinetics and fractional mixed skeletal muscle protein synthesis in humans.

    This old study suggests beta-hydroxybutyrate is not only protein sparing, but appears to promote protein synthesis.

    Current products are expensive, and tend toward transient spikes. Good for the military special forces perhaps. They are also pretty good for weight loss- I’ve lost weight while experimenting with ketone salts. And I started experimenting with them to see their effects on protein synthesis, so the fat loss is making it harder for me to assess the results.

    But it is my impression that protein + ketones = enhanced protein synthesis and that next generation supplements will focus on the post-workout/recovery period. I don’t think carbs + ketones will turn out to be a good thing, Even fats and ketones, while unlikely to be harmful, may not be ideal, because, in the presence of these exogenous ketones, the body may well decide to store fat, though this may be a very transient storage, if insulin is kept low, and the body resorts to its own fat stores during the night.

    • “Starvation ketosis, but not nutritional ketosis, is muscle-sparing. Ketone supps sans carb restriction might be.”

      • Here’s a quote:

        “Plasma concentrations of j-OHB in our subjects during the infusion of sodium DL-/3-OHB were much lower than concentrations observed in humans during fasting (34), or in poorly controlled, type I diabetic patients (35). This moderate increase in plasma concentrations of #-OHB was associated with a substantial (18-41%) decrease in leucine oxidation.”

        So, I think the effect is there, even with nutritional ketosis, but a lot of people can’t maintain nutritional ketosis while eating an adequate level of protein.

        I haven’t figured out carbs. I figure the best place for them is probably before a workout- and before any ketone supplementation. It is almost like carbs in the morning/protein + ketones during the day/ and then fats & fiber as last meal of the day. Of course, most days, carbs are optional. But this a guess based on trying to figure out how to get the most out of a very expensive product.

        • “So, I think the effect is there, even with nutritional ketosis…”

          nope, there have been too many actual human studies showing no effect…

 (this post includes the study you cited)

          • Well, my protein isn’t bro high, but it’s higher than 100g, and it seems a bit of a chore to get there.

            Can’t really see where my understanding of the situation is actually supposed to change though. It just looks like- oh hey NK isn’t protein sparing! And I’m looking specifically at increased protein synthesis under certain conditions and trying to game that.

            There’s a bodybuilder named Toney Freeman who is sponsored by KetoOS. It was an interview he gave that had me digging this stuff up. Of course, he probably gets the product for free, and obviously uses steroids, but I still thought the way he perceived them to be working was interesting:

        • Tuck

          “This moderate increase in plasma concentrations of #-OHB was associated with a substantial (18-41%) decrease in leucine oxidation.”

          Yes, leucine is metabolized to ketones for fuel. Makes sense that in the presence of ketones metabolism of leucine would go down…

    • FromPA

      How did you experiment with the ketone salts? I bought a bottle to use for experimentation, but don’t know what to do with it? For instance, do you take it before exercise? In the morning? At night?

      Also, I’m concerned about the data indicating worsening insulin and reduced lipolysis, but since I bought a bottle, I might as well do something with it.

      By the way, I couldn’t find a link to the study in part 1. I assume I missed it. Where is the link?

  • rs711

    Nice write up Bill