Fuel Stacking – Should I do it? (Ketones & Carbs)

Fuel Stacking – Should I do it? (Ketones & Carbs)

Yes, you probably should,” is the answer.

$4.50/serving, Buy here from HVMN

Some Background on Ketones

First up, forget about ketosis and your friends who are doing ketone diets. I’m not talking about that. I’m talking about ways for endurance athletes to get a bit more juice in the tank. Actually quite a bit more juice.

No doubt you’ve already optimised your glucose: fructose intake, slavishly aiming for the supposedly fixed absorption rate of 90g CHO/hour in a 2:1 or 5:4 ratio, depending on which gel manufacturer you ask! You can get more energy than that with specific kinds of ketones.

I’m far from an expert on physiology. So by way of explanation, instead look at this diagram of the Krebs/TCA Cycle and I think you will see there appear to be other ways of getting energy than from glucose/glycogen.


bhb ketone ester diol beta hydroxybutyrate


I’m talking about the bit where MCTs are converted to D-BHB (beta hydroxybutyrate)

Exogenous ketones have been around for a while as a supplement. Indeed I used some BHB from HVMN 4 years ago and was mightily impressed. Less so with the price. They were something like twenty bucks a shot and very difficult to get hold of even at that price, plus they seemed to be unavailable outside of the USA. I was training for HIMs/100-mile rides at the time and although the ketones were useful their effect only lasted under an hour. Anyway, price and availability became somewhat of a moot point when the product was taken off the market to be further developed in conjunction with the US military/DoD.

So, What’s New?

The same company (again, in conjunction with the US military) now sells a related product which it brands as Ketone-IQ. It contains the chemical R-1,3-Butanediol, which you should note is a hypoglycaemic agent (I’m guessing that’s not too good for sports) and that its effect on the human body is not widely researched. R-1,3-Butanediol is NOT prohibited by WADA/USADA.

This product will soon be globally available at a few dollars a shot. One shot has 70 calories but zero fat, protein or carbs…ZERO. Just the calories…what are calories? Energy.

The Theory

HVMN state that Ketone-IQ can be mixed with sports fuel drinks and also taken alongside caffeine.

Thus it might make some sense to ‘stack’ your fuels and add ketones to your race-day mix. Maybe.

I’m going to test it anyway to see what happens during intense or very long performances.

Tests So Far

I’ve just done one relatively fasted test so far, just because my Supersapiens glucose sensor is coming to the end of its 2-week life! This is what I got after taking it and not doing too much for the subsequent 2 hours.


I expected to see little or no impact on my blood sugar levels. This product has nothing to do with blood sugar, so that’s what I expected!

However, you can see my blood sugar did dip below 70mg/dL which is encroaching on the HYPOglycemic territory. For the next 2 hours perhaps my blood sugar was a bit lower than normal; it’s hard to say based on n=1. Dipping below 70mg/dL is, however, not something that would typically happen to me during the day but it might occasionally happen at night.

I went on to do a 30-minute tempo swim on my Vasa trainer followed by a one-hour easy run with the dog. My blood sugar levels increased up to the necessary levels for the swim, maybe that was after the Ketone-IQ wore off or maybe what was left of it in my body didn’t impair my body using sugars. The swim felt pretty easy, the easy run less so as I was tired and it was hot.

So there appeared to be no especially negative performance effects. The one positive effect I would point out is that 30 minutes after taking the shot, my brain ‘cleared’. Ketones are supposedly brain fuel and help boost concentration but I’m not especially interested in that side of things, I just thought I’d mention that that aspect of it does seem to work!

The other aspect of potential interest for endurance athletes is that Ketone-IQ might reduce inflammation and aid recovery.

Planning Consumption

OK. So I’ve not tried any of this yet in anger.

The following chart from HVMN shows how its gen 1 product (Ketone Ester) peaked early, peaked too high and quickly faded. Whereas Ketone-IQ elevates BHB from 1-4 hours….potentially very handy for your HIM or marathon.

A few sensible strategies spring to mind like taking one 30 minutes before the race starts or simply mixing it with your first drink for the bike leg. I guess the trick is to achieve this whilst also keeping blood sugars in the performance zone as well?

Helpfully the company does not say how much its product weighs, they do say it contains 10g of ketones so these results may relate to a 20kg human ie an 80kg human would need 4 shots. IDK. It’s 59ml/shot which should weigh 60g and hence enough for a 30kg human


Final Note

You might also/instead look at Ketosource’s C8 MCT powder. I often mix that with my Sunday ride fuel and it does seem to keep my energy levels up for longer (I’m not very good at refuelling). If you ever speak with Damian at Ketosource he is extremely knowledgeable and will tell you that, essentially, all the other kinds of ketones just don’t work for athletes just the MCT and 1,3 diols like HVMN.

Taste: It’s bitter but I didn’t mind it. Mixed with a uber-sweet glucose drink it’ll probably take the sickly edge off!




Buy here from HVMN


I got these free but the content it otherwise not paid for. I’ll write something later on if I think they give a performance boost. I definitely felt the Gen 1 product worked and would have bought it if i could. At the price of the Gen 2 product, it it works I will also definitely buy it for races and PB-like efforts.






2 thoughts on “Fuel Stacking – Should I do it? (Ketones & Carbs)

    1. thank you for that info. it looks good. I had a quick read-through but couldn’t find anything obviously wrong with it (non-scientist here!) other than the lower level in the study compared to the claimed optimal ones in the chart above.

      Edit: HVMN Response “This study used the racemic form (50/50 mix of R and S form) for some reason. The R form of ketones is what’s naturally present in your body and what your body actually can use. Ketone-IQ is pure R form. Because they used the racemic, not the chirally pure, it didn’t elevate ketone levels and didn’t really work. Was a weird study. ”

      Apparently, a chirally pure R form from a recent study at the University of North Georgia shows there is a significant performance increase.

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