Author: Unbonk-JP

It’s been pretty quiet in the country of sports nutrition lately: yes, there were new gels, new bars, but nothing very exciting. But here’s a new product that has the ability to get me out of my torpor: the HVMN Ketone ester drink. Let’s go for a review that contains science (a lot) and blood (a little).



1/ The company

HMVN (pronounce “Hu-man”) is a San Francisco-based company that has so far foucsed on, let’s say, exotic nutrition products. They sell “chewable coffee” cubes and a whole set of functional pills that are supposed to keep you awake or make you smart. In brief, the company was until now on my radar but as a nutritionist, their offer left me rather skeptical.
Recently, however, the folks at HVMN offered to send samples of their new product, a ketone ester drink, which aims to increase endurance performance (and much more, but we’ll talk about that later). I first said thank you, because I’m polite, and also because a bottle costs $30 (yes, you read it right), and then I accepted, making sure that the company would have no control over my review of the product. As usual, after this review, I will continue (or not) to buy these products (here with my own money. No strings attached.
HVMN starts to partner with athletes involved in high-intensity endurance sport, such as Vittoria Bussi, who recently broke the cycling hour record. Also, HVMN does not really hide its collaborations with several pro cycling teams, although none of these teams are officially sponsored by HVMN. Intriguing stuff. Most probably, it’s impossible for teams already sponsored by major nutrition brands to officially state that they are using another brand.

2/ The product and its category

Each bottle of HVMN Ketone contains 25 grams of ketone esters, more precisely (R)-3-hydroxybutyl (R)-3-hydroxybutyrate. If you don’t remember what ketone bodies are, and what their physiological role is, check that article I wrote last year. In short, ketone bodies (acetoacetate, beta-hydroxybutyrate aka BHB and acetone) are molecules produced (mostly) in periods of energy shortage by the liver, and that can be used as fuel by the brain or muscles. Here is a quick recap of how it works:


The fact that ketone bodies could positively influence performance sounded quite counter-intuitive at first. Indeed, ketone bodies are supposed to appear in a context of fasting, i.e. in a glycogen-depleted state, which is detrimental for performance. But, exercise physiologists thought of creating a « Frankenstein » metabolic situation : what would happen if you were to combine high ketone bodies level with a glycogen-loaded state ? Ideally, you would have two very efficient fuels available simultaneously : the best of both worlds.

15 years ago, scientists at the University of Oxford and the NIH started to think of the best way to unlock the potential of ketone bodies for performane, and were sponsored to do so by DARPA (Defense Research Project Agency), an agency of the US Department of Defense. Papers after papers, they showed that drinking exogenous ketone can increase drastically blood ketone levels, that this is safe, that these ketone bodies are oxidized in the muscle… All of this culminated in the 2016 Cell Metabolism article (here is my review) showing that exogenous ketone would result in a striking perfromance benefit.

So, let’s face it, this is perhaps the product that has been the most backed up by science that I’ve ever seen.

Also, while exchanging with folks at HVMN , I was very impressed by how open-minded they are at talking about the results of my own little experiments, and about potential strengths and weaknesses of their products. It seems that the academic research mindset has transferred to the members of the HVMN ketone team and this is very refreshing!

3/ Unboxing

The HVMN bottles come in nice little cardboxes of three.


When you open the box, the three little bottles are looking at you. Neat little detail : the back decoration of the three bottles actually differ from each other : I got a runner, a soccer player and a cyclist (sweet!). Also, the inside of the box recaps what the product is, what you should expect from it, and contact details : again, I appreciate the pedagogical effort and the « let’s discuss » attitude.


The HVMN Ketone packaging is quite unusual for a sport performance product : it’s not a soft gel pouch, nor it is a full-size 500 mL plastic bottle. It’s a small transparent plastic bottle, which reminds me of a plastic version of a hip flask.


Note that you do get 25 g of BHB ester (called here “Pure delta G ketones”) in a 65 mL transparent drink. This is comparable to the amount of carbohydrates you would get from a classic 500 mL sports drink (about 30-40 grams of sugars).

Finally, the folks at HVMN lend me a kit to measure my blood glucose and my BHB levels.


I had only 5 strips each so I obviously could not test all possible situations. And there were billions of ideas of situations in which a BHB measurement could have been interesting, but I tried to focus on getting to know how the product works for me. More on that in a second.

4/ Tasting

So, I feel like I need to give a bit more context here.
Ketone drinks have been around for a few years, but have never become mainstream. There are two main reasons for this : the first one is price (those things were and are still expensive) and the second one is … taste… Others have described the experience of ketone-based drinks as drinking « jet fuel ». You can easily fall down the youtube rabbit hole watching videos of people drinking ketone drinks and desperately trying to wash their mouth…

ketone-ester-matt-tasteA snapshot of the YouTubers at “Keto Connect” trying a random ketone drink.

So, based on this context, you can imagine that 1/ I was pretty curious to taste the new HVMN Ketone drink and see how it compares to other ketone drinks and 2/ my expectations were frankly pretty low.

A second point I need to make is that not all ketone drinks are created equal. Most older drinks are based on ketone salts, while the HVMN ketone drink (like a few other drinks, mostly those on the very expensive side) are ketone esters. While I haven’t specifically tasted all the ketone drinks out there, it is generally assumed that ketone salts will be the less tasty ones (to put it mildly), while ketone esters should me more palatable.

Enough details, time to drink !


Let’s be honest : drinking a bottle of HVMN ketone is not an extremely pleasant experience.

The first obvious thing to mention is that the drink is extremely bitter. Not the kind of fresh bitterness of an IPA, but rather a long bitter aftertaste. It persists on the tongue for a few minutes, and cannot really be washed away with water. It is not unbearable though, but not enjoyable either.

Another thing that struck me is the relative discrepancy between the pleasant smell and the taste. The drink is lightly flavored and sweetened with stevia extracts, so you would expect the drink to taste sweet. It does indeed but the bitterness clearly is unexpected.

Eventually, can we blame HVMN for making a poor-tasting drink ? Honestly, I can’t. I worked in the past to make amino acid-based drinks taste good when single amino acids just taste like rotten meat. You can work with artifical flavors, you can try to change the concentrations, you can play with the texture of the matrix… but in the end, you can’t make a pig fly. If the raw ingredient tastes bad and you need a lot of it in your final product, there is not much that you can do. HVMN did concentrate the BHB esters into a small drink, which limits the duration of the unpleasant experience, and did add a distracting flavor. There is not much else to do than accepting that BHB esters taste bad. They may taste much better than the salts, though (but again, my practical experience with BHB salts is limited).

5/ Does it elevate my ketone levels and how ?

The first thing I wanted to test is how much a bottle of HVMN Ketone would elevate my BHB levels and what the kinetic of the blood response will be. So, I used the kit I got from HVMN.


Now, remember I had only 5 measurement strips. So, I forgot about the duplicate or triplicate measurements that I would normally do in the lab with such measurement devices.
Based on the published articles, I decided to run a 4 point kinetic curve (0-30-60-120 minutes) and save one strip for other purposes. I started the test about two hours after lunch : this is the time I would reasonably consider waiting after a meal before going for a run. Then, I waited for two hours… I did not do any exercise, because I wanted to see how my body would handle the ketones at rest , and not how much my body burns them while exercising. Here is what I found :


So, my BHB were already extremely high after 30 minutes. These values would be similar to the type of ketosis achieved after several days of fasting. So, it’s pretty crazy to see that such a small flask can induce such levels in such a short time. The BHB levels plateaued after 60 minutes and stayed surprisingly high after 120 minutes. I have to say that my peak levels were lower than what is claimed on the box (3 to 5 mol/L), but I could in principle adapt the dose to my body weight (72 kgs) and drink a bit more than one flask to achieve a higher ketosis.

Lastly, I measured by BHB levels 30 minutes into a run, which was also 30 min after I drank a full bottle of HVMN Ketone. I had a value of 2.9 mmol/L, similar to my value in resting condition. It was good to see that I did absorb the ketones while running, but I somehow expected that I would burn some already after 30 minutes, and thus that I would have a lower value. Anyway, it was my last strip so I did not really follow-up on this. I got in touch with the head of science of HVMN who nicely walked me through the evidence they have that BHB are absorbed and oxidised by the muscle. The evidence is solid and so, I have no doubt that I did as well burn the ketones later in the run. The take home message probably is that the first 30 minutes after ingestion are still a period where absorption is the main determinant of BHB blood concentrations.


6/ Subjective feeling during exercise

Now that I knew better how ketones would peak in my blood, there are lots of important questions I still wanted to answer : would I tolerate them well ? How would I feel with such a high ketosis ? Would I feel a performance boost ? How would I cope with the taste in the long run ? …

As usual, I took the drinks with me in a variety of situations : long runs, short runs, multi-hour bike rides, multi-day bike rides , … and I think I now have a pretty good grasp on how the product affects me. As usual, take my thoughts with a grain of salt : these are the results of pseudo-scientific experiments on myself (n=1).


TASTE / GATROINTESTINAL ISSUES? I did not get any gastrointestinal issues with the HVMN Ketone drink, neither at rest nor during exercise. After a few weeks of testing, I expected the bitter aftertaste and it did not bother me excessively anymore. I still don’t enjoy it, but I can drink it.

PERFORMANCE BENEFIT? While running or riding at moderate intensities, I did not instantly feel a performance boost. This is OK, because the benefit of ketones is supposed to appear at later stages or at higher intensities (see the scientific explanation here). At later stages though, i.e. 1h30 to 2h into the run/ride, I had the impression that I had some significant energy left. In cases where I had two bottle of HVMN Ketones (one before the start, and one 1h30 into the run/ride), this feeling of performance boost was sustained even longer.

COGNITIVE ABILITY? The one hour that follows ingestion of HVMN ketone is an interesting one : the subjective feeling is pretty hard to describe. I systematically got the impression that I was more alert, more present. Physiologically, it makes sense that a « fasting » fuel increases alertness, making an individual more prone to look for food, or increasing the changes of a weakened organism to escape predators. The increased alertness I felt is not necessarily pleasant though, nor it is unpleasant. It was a bit like having a light headache but without the negative aspects of it: I can see how this may translate into cognitive benefits.

=> All in all, I was pretty impressed with how different I felt in terms of mental focus and physical performance late in workouts. I did not become Eliud Kipchoge but I can see that this product had a performance-enhancing effect on me, as shown in several scientific articles before.
The question that remains is whether these effects are really specific to ketone bodies : I also tend to be more focused after a big load of carbs, as well as I tend to feel better later in my runs when I have sports drinks. In the end, performance and cognitive benefits do not result from the nutrients themselves, but from the fact that the brain and muscle cells can oxidize a fuel and function properly. There is, however, some evidence out there to suggest that ketone bodies have an added benefit over sugars : when compared to isocaloric CHO drinks, KE+CHO had an added benefit on performance (COX). So, I would tend to say that my positive experience may have been specific to ketones.

Recap and last thoughts

In summary, HVMN Ketone pushes the boundaries of sports nutrition science with an intriguing product. Knowing the research that has been going on for years in the field, I expected the ketone ester drink to be efficient in terms of endurance performance and cognition, but I also expected it to taste funny. And the product is exactly what I had expected, with its pros and cons.

So, would I buy it? I would consider buying a few bottles in prevision of a race for which I badly want to get a PR, and for some training sessions leading to the race. I’m not a pro, so the budget and the taste are still no-gos for me to use HVMN Ketone on a regular basis. Also, I would be curious to see studies investigating the metabolic adaptations to a chronic exposure of ketone esters drinks.

Practically, I would consider mixing the ketones with a carbohydrate drink: this seems to correspond to the best evidence-based fueling strategy available to date. It would also make the ketones taste better.

Finally, I’d like to state once again that this product, with its strengths and weaknesses, is a stunning example of an innovation that started on a lab bench and went through extensive scientific validation before hitting the market. I congratulate HVMN for doing this successfully, and I wish more products like this could follow this approach!


Photo Chris Lawrence (

Lots of us woke up early (or stayed up late!) to watch the sub 2-hour marathon attempt by the Nike squad. Kipchoge came up 25 seconds shy of the goal in an obviously well-prepared race. Of course, I watched how it went with the nutrition! And here are the 4 things that I learned.

1/ A pre-race strategy was used, with reports that Kipchoge had a full bottle (0.5 L) of the Maurten hydrogel drink before the race (read my product review). The reports, however, don’t further precise the concentration of the drink nor the pre-race timing.

2/ It was clear that the 3 Nike runners, on the contrary to what happens in IAAF-certified city races, had access to personalised drinks very often in the race. In fact, each of the runners, got a small vial from their crew at each loop, i.e. every 2.4 km. It seems that they have been instructed to drink the full vial, since you could see them carefully emptying the bottle each time. Here is a screenshot of Kipchoge drinking in one of the last loops.


Screenshot from Nike official footage

3/ Each of the small vial contained 50 mL of the Mix320 PRO drink by Maurten (the Swedish brand providing the drinks for the breaking2 attempt). This led to a total ingested volume of 0.9L, which corresponds to a total of 150 grams of carbohydrates over the whole race (according to Maurten’s info).

4/ If we calculate it, this means that Kipchoge’s drink was a 16% CHO drink. Although it was claimed that each drink was highly individualized, it seems to indicate that Kipchoge used a drink pretty close to the commercially available version (which contains 79g for 500 mL).

To conclude, let’s see how it compares to what happens in a normal race. In the study I was mentioning in a previous post, sports scientists of the University of Glasgow examined the drinking behaviour of 10 elite marathon runners during races (average finishing time of 2:06:31). The study found that these elite runners drank on average during 25.5 seconds in the race, resulting in a fluid intake of about 0.5 Liters / hour. Basically, Kipchoge in his very controlled attempt is close to the average fluid intake in race conditions.

Interestingly,  although the study included almost exclusively marathon winners, the fluid intake ranged from as low as 78 mL to more than 2 L. Thus, it indicates that a wide range of hydration strategy may lead to marathon success…

One thing is certain though… It’s probably wiser if you let your competitors finish your beer!

Thanks for reading!


Photo AP (


Picture by Chris Lawrence

Here we are…

The Nike attempt to break the 2-hour marathon barrier will happen very soon, most likely the 6th, 7th or 8th of May.  It will be possible to watch the race live (though I don’t know where it will be broadcasted yet) and, hopefully, get a full understanding of the strategies chosen by the Nike team (including pacing and nutrition).

A crucial part of the strategy was/is the choice of the Monza Fromula 1 track, rather than a more traditional city location. Nike justifies the choice of Monza as follows :

The temperature hovers around 12 degrees Celsius and vapor pressure is under 12mmHg. Additionally, skies are typically overcast (minimizing heat load on the runners) and air currents don’t exhibit drastic directional shifts — thanks to the course being perfectly situated off shore and amid many trees.”

But another interesting feature for me is the fact that the course is a loop. A very short loop of 2.4 km. For official marathons, IAAF rule 240 states that aid stations should be available at least every  5 km; and in fact, there are mostly located every 5 km in major marathon events. Here, Nike runners will pass by an aid station every 2.4 km : could that make a difference? Nike indeed mentions the length of the loop as an optimal length for a “perfect management of […] hydration, (and) nutrition“. What does science say about this claim?

1/ Is dehydration in elite runners a performance-limiting factor?

There is a long and furious debate about what “adequate” hydration for endurance performance actually means. I don’t want to get into this today, but one thing is certain: losing a lot of body weight (presumably due to water and glycogen loss) doesn’t seem to be a problem for elite runners.

In an interesting study, sports scientists of the University of Glasgow examined the drinking behaviour of 10 elite marathon runners during a race. And by the way, among these 10 elites, 9 won and 1 finished 2nd of some of the major city marathons (average finishing time of 2:06:31). The study found that these elite runners drank on average during 25.5 seconds in the race, resulting in a fluid intake of about 0.5 Liters / hour. The authors estimated that such fluid intake would result in about 9% of loss of body weight, and confirmed this by measuring an almost 10% body weight loss in the 2009 Dubai marathon winner.

Ok, you may think “just because the winners finished highly dehydrated doesn’t mean that this is the best strategy… Maybe they would have done better in a well-hydrated state?”

Well, not sure… Lots of studies have tried to measure the impact on endurance performance of drinking “naturally”, i.e. according to thirst, vs drinking more, i.e. to prevent a loss of body weight above 2%. The results are, like often, mixed, but the general consensus is that 1/ drinking according to thirst is usually an optimal strategy, 2/ losing a lot of body weight during a race does not necessarily lead to a poor performance (at least not in elite runners).

In conclusion, there is not so much data around to support that a better hydration status during the race enhances performance in elite athletes (I am not talking about amateur runners here). There is even a striking prevalence of dehydration (or at least loss of body weight) in top marathon runners.


 Picture by Robert F. Bukaty

2/ If it’s not about drinking more, is there something about drinking/eating more often?

Is it more efficient to drink X mL per hour in small sips or in a few big ones? As basic as the question may sound, there are not many studies on this question in elite runners. So… we need to rely on gut feelings. I would say it is most probably a good idea to segment fluid and food intake in small bites or sips to reduce gastrointestinal load. Keeping the fluid and nutrients coming at a constant rate to the stomach may reduce gastrointestinal stress and increase intestinal absorption. Still, whether there is a real difference in gastrointestinal comfort or intestinal absorption when you drink every 2.4 km instead of 5 km is just not known.

In real life, grabbing a bottle at each round will likely cost a few seconds or at least, some energy to slow down and accelerate again. If drinking at each loop is the strategy followed by the Nike runners, they will most probably have the pacers collect the bottle for the 3 main runners.

3/ Do frequent aid stations help cooling?

We all know the effects of air temperature on endurance performance and the importance to keep the core temperature down. But Monza has in part been chosen because the temperatures are in the 10 to 14°C range in the mornings of May. Thus, atmospheric conditions should be optimal without active cooling. Whether supplemental cooling during the race may improve performance in race conditions that already are near optimal remains unknown. There may be some practical real life data on this, but no published studies to my knowledge.


In a major marathon, aid stations are staggered every 5 km, meaning that elite runners get the opportunity to drink every 15 minutes. In Monza, the Nike runners will get the opportunity to refuel twice more often. There is really not enough published data in the scientific literature to conclude whether the more frequent availability of fluid and nutrients improves performance in elite runners.  But in the context of a sub 2hr attempt, each second may count… so even in the absence of scientific literature published, Nike may want to try things out based on the runners’ feelings or their own collected data. And beyond nutrition, a small loop might be ideal for the Nike runners to get frequent feedback about their pace, inputs from their team, changes of pacers…

Let’s see how all this unfolds!




I feel very excited about this review! Today, we are testing one of the most exciting innovations in the sports drink industry. It might be a game changer. And the original idea is so simple.

1/ Maurten, the company:

Maurten is a Swedish-based startup and a new player in the sports drink industry. The company is best known for its collaboration with top elite athletes in the attempt to break the 2-hour marathon barrier, as I recently reported (here).

The Swedish founders have taken a new approach in trying to solve one of the major performance-limiting factors in long distance runners : gastrointestinal discomfort. The idea is to “encapsulate” carbohydrates in gels, thus circumventing the issues that usually arise with a highly-concentrated drinks (see below).

On top of this, the gels themselves are made of long carbohydrate polymers, further increasing the total amount of carbohydrates delivered by the drink… Clever… All in all, Maurten claim they have manufactured the most carbohydrate-rich sports drink in the world.

2/ The product and its category:

Since my last article, Maurten revealed the composition of its new drinks. The drinks are made of two parts: on one hand, you have simple carbohydrates, glucose and fructose, as well as some salt… Pretty basic sports drink stuff. On the other hand, pectine and sodium alginate are there to form a hydrogel, ie a three-dimensional molecular network that can contain a lot of water. The theoretical result of this is a gelly-like structure made of long chain carbohydrates (ie pectine and alginate) that has salt, glucose and fructose trapped in it. But, because it would be highly impractical to swallow a 500 mL gel while running at 20 km/h, the drink is supposed to be fluid in normal conditions, and only form a gel in the stomach, ie at low pH.

The whole idea behind these new drinks is to reduce the gastrointestinal stress that comes with highly concentrated carbohydrate solutions. Hydrogels should speed up gastric emptying and, thus, enhance intestinal carbohydrate absorption, as old studies have suggested (here, and here). If this is really the case, hydrogel drinks might just be the biggest game changer in the sports drink industry since … the invention of the sports drinks…

To be fully transparent, I have to make a little “DC-Rainmaker” disclaimer : I got 5 samples of the Drink Mix 160 and 320 (and a plastic bottle) from Maurten after I talked to them on Twitter. This allowed me to test these new drinks before everyone else and to have enough time to run with the drinks. After that, if I like the drinks, I will just buy my own.

3/ Unboxing:

Maurten’s hydrogel drinks come in two versions: the “Drink Mix 160” and its big brother the “Drink Mix 320 PRO”.


The”Drink Mix 160″ comes in individual pouches of 40g …

160-front-mh… and the “Drink Mix 320 PRO” is twice bigger (80g!!!).


From the 2 following pictures, the differences between the 2 versions of the drink seem minimal… but they are not! The 160 drink will make a 500 mL drink containing 39 g of carbohydrates, i.e. an 8% carbohydrate solution : this is in the higher range for a sports drink, but not unheard of. The 320 drink, however, results in 79 g of carbohydrates in 500 mL, which makes it a 16% carbohydrate solution. This time, we’re talking about the type of concentrations that have almost always led to gastrointestinal discomfort during intense exercise.

Here is the back of the “160” pouch …


… and the back of the “320” pouch. Note the 99 g of CHO / 100g!


Let’s start the unboxing! Starting with the “Drink Mix 160”.


There is not so much surprise when opening the pouch. It is a typical sports drink powder. And you get the 40 g that you expected.

Looking closer, we detect some small clumps.


A closer look at the small clumps. I’m not sure if this is actually made on purpose (to improve solubility), or if this is the result of a caking process (the product does not contain any anti-caking agents). It will be an important thing to know, because if the clumps keep forming, it might impair the product solubility.


In terms of appearance, the “320 PRO” Mix is almost not distinguishable from the “160”. So, I spare you the pictures and head straight to the tasting!

4/ Tasting:

So, I took my official Maurten bottle…


… filled it up to the first edge …


… shaked for a few seconds and tatatata…


As expected, it was not a hydrogel yet. At first, the drink was indeed relatively fluid.

As you can see, it was not fully transparent though. It didn’t seem like there were any solid particles in suspension. Rather, we could see a lot of very small bubbles that slowly cleared over time.


The Drink Mix 160 and 320 Pro do not contain any flavoring nor coloring agents. Thus, I didn’t really expect anything else than a tasteless but (very) sweet drink. And yes, it is sweet… very sweet… And there is no flavor to distract your taste buds!


As mentioned earlier, the drinks are still fluid but there is the (maybe false) impression that there are particles swimming in them, especially in the most concentrated “320 PRO” Mix. They do clear over time, though, and it is very likely not an issue, since the drinks are made to be prepared before the workout has even begun.


This was expected, but the drinks, and especially the “320 PRO” Mix are intensely sweet. They seem to have the distinctive agressive sweetness of fructose. Drinking several sips require motivation and, very likely, the strong belief that the drinks will enhance your performance. There is no flavor, which to my mind is a good thing, as adding flavor on top of such a sweet base would probably result in a disaster. In this case, simple is better.

5/ Does it make a hydrogel?

The hydrogels are supposed to form only in an acidic environment, i.e. only in the stomach (which should have a pH in the 2 to 4 range). To visualize the hydrogel, I had no other choice that to make a small experiment with lemon juice.

Below is the result of the experiment!

The short answer is : Yes, it did make a hydrogel… And a pretty nice one. It was pretty amazing to watch the fluid turn into a gel. In this case, I could not transform the whole drink into a gel. Just the upper layer which got in contact with the lemon juice did form a gel. But, given the environment in the stomach, I would say that it is very likely that the the whole drink turns into a similar hydrogel in the stomach.


6/ Situation test:

Now that we know that the Maurten drinks do form hydrogel at low pH, there are lots of important questions that I still wanted to answer: would I tolerate them well? Would I feel better than with a normal sports drink? How would I cope with the sweet taste on longer runs? …

So, I took the 160 and the 320 mixes with me on various occasions. The most interesting one was a 30 km run along the Zurich lake with the most concentrated 320 Mix. This run basically summarized all pros and cons of the Maurten drinks.

a. I had no gastrointestinal issues with the hydrogels, no cramps, no bloating, nothing… This is pretty amazing, giving the fact that the 30 k run was pretty intense (for me) and on a hot day.


b. The sweet taste of the “320 PRO” Mix (the most concentrated of the 2 Maurten hydrogels) is somewhat difficult to tolerate over the long term. I found it useful to regularly rinse my mouth with plain water, just to temporarily remove the sweet taste.

img_20170408_161603c. I felt subjectively good with these drinks, including past the 25k mark of my long run. If I felt better than with “normal” sports drinks? It is of course hard to say and highly subjective. I am definitely willing to keep on using these drinks, but I would like to see a scientific demonstration that the high carbohydrate intake achieved with the Maurten drinks has a beneficial effect on performance compared to classic sports drinks.

7/ Nutrition:

Here is a recap of the nutrition sheets of the Maurten 160 and 320 PRO Drinks. In both cases, 1 serving is dissolved in 500 mL of water. Overall, the Drink Mix 160 is a 8% CHO drink and the Drink Mix 320 PRO is a 16% CHO drink.

  Drink Mix 160  Drink Mix 320 PRO
1 serving = 40 g 100 g 1 serving = 80 g 100 g
 Energy (kcal) 160 400 320 400
 Carbohydrate (g) 39 99 79 99
 Sugar (g) 13 32 33 41
Protein (g) 0 0 0 0
Fiber (g) ? ? ? ?
Salt (mg) 400 1000 500 630

It is interesting to note that in both cases, the ingredient list is very short: Maltodextrin, Fructose, Pectin, Sodium Alginate, Sodium Chloride. To me, this illustrates some great things about the drink composition and raises a few more questions.

– no additives! The drinks are formulated without preservatives or technical adjuvants, such as solubilizers or anti-caking agents. This is a great thing as some of the usual additives in sports drinks have an upper tolerable limit that might be reached in situation of high training load.

– no artificial flavor! As mentioned earlier, adding a flavor on an already very sweet base is very complex and may overload the taste buds. To me, it is definitely a good point to keep things simple.

– the glucose molecules seem to be largely brought by maltodextrins (hydrolyzed starch). Maltodextrins are less sweet that single glucose (or even smaller polymers), leading to a reduction of the sweet taste. Playing with the hydrolysis degree of the maltodextrins (ie having bigger polymers) may further reduce the sweetness.




The Maurten Drinks get a 5/5 because they open a whole new category in the world of sports drinks. My experience with the drinks was very positive: I could tolerate them well and felt subjectively strong during long runs.


Overall, the quality of the Maurten powdered drinks is very good. The drinks come in handy individual pouches and the preparation is very easy. The solubility is a minor issue, though, especially when it comes to instantly dissolving 90 g of sugar in 500 mL of water (but I don’t see any solution to this, while keeping the ingredient list so nice and simple).


With a very high carbohydrate concentration and no artificial flavor, the Maurten drinks taste … sweet … The use of maltodextrins instead of dextrose probably has already helped decreasing the sweet taste. The absence of flavor may be surprising at first but is very likely a good thing for your taste buds.


Yes, the Maurten Drinks (especially the 320 Pro) allow for the first time a very high carbohydrate intake during intense workouts. My impression is that the hydrogels circumvent the gastrointestinal discomfort that normally results from the intake of highly concentrated drinks. I give only a 4/5 because I would like to see solid scientific data showing that the extremely high carbohydrate intake in the form of hydrogel does indeed a. speed up gastric emptying, b. increase the oxidation of exogenous carbohydrates by the muscles and, c. increase performance compared to classic sports drinks.

Overall, it’s 16/20 for the Maurten Drink Mixes 160 & 320 PRO!!!

In short, it’s a whole new page of the sports drink industry that Maurten is currently writing. My first impression is very positive but I’d like to see more solid scientific data!



Recently, I became a run commuter. It changed my everyday life and it definitely impacted my training and my nutrition.

I have to say that my way to work is an easy 5k, and it’s mostly downhill in the mornings (when my motivation is low). I can even get a view on the Alps when the weather cooperates. So, overall, yes, I’m lucky, and I have near-perfect conditions for run commuting.

There were however a few things that I found really challenging and I’d like to share them here in the hope that it will encourage you to run commute (or help you to continue). For me, the challenge was (and still is) quadruple: 1/ Packing, 2/ Transitioning efficiently, 3/ Staying motivated, 4/ Handling nutrition.

1/ Packing

a. Finding the right backpack

There is something that struck me when I started to run to work… It is damn hard to find a good running backapck with enough volume!


Yes, I had a good running vest for ultras but it can barely contain a rain jacket and 2 liters of water… With all the clothes that you need to carry, and maybe a small laptop (like a 11-13″ thin Macbook air or alike), you would need a 20 Liter backpack. I would say that a good backpack probably is one of the key elements for the long term success of your commutes. There are blogs that test backpacks for run commuters, I would definitely have a look before investing (have a look here). Personally, I gave my skimo bag (Dynafit RC20) a try, and so far, I am very happy with it. It’s  waterproof (for rainy days) and so light that I sometimes just forget that it’s on my back.

b. Reducing weight

Even with a good backpack, it is not great to carry a lot of weight on your shoulders while running twice a day. I progressively learn to reduce the weight and volume of my stuff.

  • small / packable shoes. If you work in a relaxed environment like me, no need to carry heavy leather shoes with you. It is even better if you can leave a pair of shoes under your desk, so that you don’t even need to carry anything.


  • small / packable jacket. In Switzerland, it’s not uncommon to wear a down jacket to work. A down jacket is easy to pack and there is no need to worry about the way they will look like.


  • Empty your wallet! Do you really need all these cards?


  • Don’t take all your keys with you.


  • If you can’t leave towel and shower gel at work, pick a microfiber towel rather than a bulky one.


  • Transfer shower gel into a smaller vial.


Better is of course if you can leave stuff at work and shower directly there. It’s not my case but maybe you are luckier! That will make your backpack much lighter!

c. Being ready for weather changes

The main problem with the weather is that it can change! After a sunny morning commute, you may face some rain in the evening, and you’d better be prepared! Most of the backpacks are only mildly waterproof. Always have with you thick plastic bags (for clothes, and eventually laptop), and ziplock bags (for small electronic equipment).



2/ Transitioning efficiently

While the run itself is the easy part (after all, it’s just running with a backpack, duh), it gets more complicated when you reach your workplace. You are most often wearing sport tights, you sweat, and none of your colleagues is willing to sit next to you.

a. Finding a shower


If you have a shower at work, problem solved. If it’s not the case, like for me, do the following:

  • talk to your colleagues, there may be a shower at another floor or in the company next door.
  • If you are unlucky, locate a gym next to your office. It may cost you something, but try to negotiate the membership fees if you only plan to shower there. After all, you are saving the costs of public transport, so all in all, you are still saving money.

b. Drying your clothes during the day

Find a place where you can leave your clothes to dry during the day. If some places have a shower, they don’t always encourage the exhibition of smelly t-shirts during working hours. I still haven’t found a great idea for this problem. This is a trial-and-error process!


3/ Staying motivated

Like people around you will probably tell you: “it is insane to wake up in the morning to go running”. You may not agree with this (I definitely don’t), but I think it is however totally normal to have a low motivation from times to times. Here are some tips to help you deal with this.

a. Prepare your backpack and clothes the day before

Human behavior is often driven by the principle of least effort! If everything is ready to run commute, it will cost you more time and effort to unpack everything and get ready to commute with public transport. So, you’ll run. As simple as that!

b. Adjust your training

Running to work seriously increases your weekly mileage. Adapt your training progressively to this new training load. If you are preparing, let’s say, a marathon, remove the low intensity sessions from your training program and focus on quality (i.e. interval, …) sessions.

c. Incorporate rewards into your routine

Besides the principle of least effort, our behaviors are also driven by the obtention of a reward! Rewarding you with a stop at your favorite coffee place, your favorite bakery, or whatever pleases you may be a great supplementary source of motivation.


4. Handling nutrition

a. Find out how much you can eat in the morning

It is an important part of your success. There is indeed a very limited amount of time between the end of your breakfast and the start of the run. For me, there is typically only a 15 min window. So, a monster breakfast with eggs and waffles is out of question. It took me about two weeks of trials to find out that my stomach could tolerate :

  • an espresso
  • half a bowl of muesli  OR a bit more than a toast with jam OR a fruit salad

Again, it is a trial and error process. You may even consider to skip the pre-run breakfast and have it later at work. Reduction of gastrointestinal discomfort should be your priority.alex-kotomanov-190961

b. Finish breakfast at work

Reward yourself with a good breakfast at work! This can be part of your routine and help you stay motivated. Don’t overeat, just try to finish breakfast as if you were still at home.

c. Become a healthy snacker

Running twice a day, even short distances, may impact your appetite. According to the people I talked to and my own experience, it doesn’t make you have bigger meals, but it makes you want to eat more frequently. In Research lingo, it “decreases satiety” but not “satiation”. To deal with this, buy fruits and nuts and constantly have them on your desk. Like this, you will stay away from unhealthy temptations.



Run commuting to work changed my philosophy of urban transportation. It increased the volume of my training. I may even say that it made better and more focused at work.

But it doesn’t come from alone. Don’t neglect the impact of the material. And find the conditions that work for you using trial and error (yes, you may forget to pack extra socks one day or the other).

All the tips above need to be adapted for your work and your environment (commuting twice or once a day, shower availability, capacity of leaving things at the office, …). But, believe me, it is worth the effort!


After long and/or intense training sessions, recovery can be optimized with the help of adequate nutrition. The idea is, on one hand, to quickly restore muscle glycogen levels and, on the other hand, to support the re-synthesis of muscle proteins. Think about athletes repeating high intensity efforts within days, or even hours: perfect recovery is especially relevant for them.

Based on numerous research reports, it has become pretty clear that a mix of carbohydrates and proteins taken during the first hours after a workout was both practical and efficient to improve subsequent performance. Recovery drinks following these principles suddenly appeared on the sports nutrition market. Today, we are testing one of them: the Recovery drink from Aptonia. And, yes, it’s chocolate flavor!


1/ Aptonia, the company:

Aptonia is the sports nutrition brand of the Decathlon Group, one of the world’s largest retailers of sports equipment. Within a giant group, Aptonia is a relatively small brand, producing diverse nutritional products, ranging from cheap cereal bars to high-end sports drinks. I’ll say it upfront, I know the group pretty well because I have done my master thesis in collaboration with Aptonia and worked another 18 months in the R&D department of Decathlon. This was about 6 years ago. Then, I moved on and transitioned to an academic carrer in Switzerland. I am definitely biased because I know the brand from the inside and have a pre-conceived idea of what they do great and where they could improve, but I will try to review their Recovery Drink as objective as possible… oh.. and obviously, I am also biased because it’s chocolate flavor.

2/ The product and its category:

All sports nutrition brands have their own version of a recovery drink… they have to. I am not sure how well they sell, though. Recovery drinks are mostly used by very ambitioned amateurs or pro athletes, and this of course is a niche market. Also, it’s most probably not the core of Aptonia’s customers, because serious runners tend to consider other sports shops than Decathlon (I’m not saying they are right or wrong, that’s just the way it is).

Interestingly though, Aptonia displays on the package of its drink a “doping-free” label, a feature that may be of interest for serious athletes concerned about product contamination.


Indeed, a lot of sports nutrition products, notably those bought online from non-established vendors, contain traces of banned substances. On top of potential health issues, this can cause an unexpected positive test result. Here, Aptonia’s recovery drink shows the French norm NF94-001. Basically, it means that a list of good practices has been followed during ingredient sourcing, product manufacturing, packaging and transport, to avoid contamination by unwanted substances. For most of us amateur athletes, it does not make a huge difference but “doping free” labels have slowly become standard within the sports nutrition industry. Aptonia followed the trend.

3/ Unboxing:

First, a little message to Aptonia: “Dear Aptonia, would you please stop making shiny packages so that I can take decent pictures? Thanks!”

With this being said, let’s have a look at the package. While the front is pretty neat, there is a big problem with the back of the pack… It’s written very small and it’s overcrowded with information… Seriously, it is a nightmare to find simple things like the list of ingredients or the nutritional values. I’m sure that some people give up and choose another product just because they can’t identify quick enough what is in it.


As if it was not enough, Aptonia chooses to have all the languages on Earth on the same package. For this, they use a clever system of sticky leaflet. I mean, clever… it’s even less readable than the rest. Aptonia does this because they have to display the official languages of the countries in which they sell their products. I understand this, but maybe it’s time to have country-specific packages. Or maybe just 2 different packages with just 50% of the languages on each would be a huge improvement.




A positive point is an efficient “ziploc” system that allows to close the pouch nicely until next to use.


Inside is the powdered drink with a beautiful orange spoon.


Transferred into a glass, we see a light brown powder that is not entirely homogenous. Most noticeable are the big and shiny sucrose particles.


4/ Tasting:

Aptonia indicates that the drink needs to be prepared with 64 g of powder dissolved into 300 mL of water. 64 g should be about 3 full spoons.

1 spoon…

spoon1And after 3 full spoons, I actually reached 63 grams, which is damn close to the 64 g I aimed for. So, trust the magic orange spoon, it’s in the right ballpark.


Transferred into a shaker, we can see that the powder actually represents a non negligible volume.


Pretty excited to try the chocolate drink, I followed Aptonia’s recommendations and added 300 mL of water into the shaker, shaked … and got this…


The drink looked pretty concentrated and heavy to me, and the foam was … let’s say … not appetizing…


I still had a sip and it was way too concentrated, too thick, too sweet…

So, I paused and realized that dissolving 64 g, among which are more than 40 g of carbohydrates, into 300 mL doesn’t make much sense. It makes a 12 % carbohydrate solution (+ proteins)… for comparison, most of the sports drinks are 6-7% solutions. And it seems to be a pretty bad idea to drink a highly concentrated solution right after an intense workout session. Also, it is a recovery drink… and you know what else is important during recovery… hydration!

Consequently, I decided to add some more fluid and added up another 400 mL of milk to the solution. I chose milk because, in my experience, it makes chocolate drinks taste better and because it contains the carbohydrates and proteins that may further help recovery.

And the magic happened. The color got better…


Even the foam looked better!


In these conditions, the drink was much more pleasant! And I could start drawing my favorite tasting graphs! Remember that I can’t say whether you will like the product or not. I can only try to describe the texture and flavor as objectively as possible. So, if my “objective” description matches what you may like, go buy the product and reach out on social media to give your opinion!

graph1-apto graph2-apto

Eventually, I am pretty happy about the taste of the drink. On top of that, I had no GI issues or feeling of bloating like I might have with other recovery product. All in all, once you found out the much-needed adaptations, it is a pleasant chocolate drink.


6/ Nutrition:

How does Aptonia’s recovery drink compare to the current scientific guidelines for post-exercise nutritional recovery? Well, it depends how you see it … Here is a quick recap of what Science says.

To maximize the rate at which muscle glycogen is resynthesized, large amounts of carbohydrates are required (1.0 to 1.8 grams of carbohydrates / hour / kg of body weight), and this during the 2 to 5 hours following exercise. When this carbohydrate intake is reached, the addition of proteins or amino acids does not further increase the rate of muscle glycogen resynthesis. The addition of proteins, however, does 1/ increase the rate of glycogen synthesis when carbohydrate intake is suboptimal (below 1.0 g/kg/h) and 2/ stimulate post-exercise muscle protein anabolism.

Practically speaking, it means that a mix of carbohydrates and proteins bringing about 60 to 80 grams of carbohydrates and about 20 to 25 grams of proteins per hour may be efficient to speed up muscle glycogen and support muscle protein synthesis. As you can see, the nutritional values of the final 700 mL drink I prepared (64 g powder + 300 mL water + about 400 mL semi-skimmed milk) are pretty close to it!

   / 3 spoons (64 g)  / final 700 mL drink
 Energy (kcal) 226 454
 Carbohydrate (g) / Sugar (g) 41 / 37.1 61 / 57.1
 Fat (g) / Saturated fat (g) 0.6 / 0.4 11 / 6.4
Protein (g) 14.1 28.1
Fiber (g)  –
Salt (mg)  – 400
Sodium (mg) 173 330
Calcium (mg)  ? 480 from milk
Magnesium (mg) 190 238
Potassium (mg) 960 1630

2 more things about the ingredient list:

1/ the recovery drink contains several antioxidant vitamins. It is now clear that the chronic intake of antioxidants post-exercise reduces the natural antioxidant capacities of our muscles. In other words, it may not be a great idea to drink this recovery drink after each of your training sessions, because you may disturb the natural capacity of your muscle to buffer the exercise-induced reactive oxygen species. I would preferably use this drink only for competition days.

2/ In this recovery drink, proteins are brought by powdered milk (so containing all types of milk proteins including caseins and whey) and by whey protein isolate. There is a lot of debate about the type of milk proteins that may be the most efficient for muscle recovery and, of course, there is no clear answer to this question. So, I can’t really comment on the choice to mix the two, except that it is probably a good idea in terms of taste, because powdered milk tastes much better than whey concentrates or isolates.




In terms of usage, Aptonia’s recovery drink gets a 3 out of 5! The powder dissolves easily, the product comes with a spoon that is surprisingly precise and the package can be closed properly after use. But the unclarity of the label is for me a big problem. It is already difficult enough to scan through the ingredient list or the nutritional values on a normal package… this product is beyond limits!


The quality of the powder is overall pretty good. Too bad that the shiny package with a book stuck on it does not help to give a good first impression.


I don’t really understand how Aptonia can advise to add only 300 mL of water to more than 60 g of powder… It just makes the drink so thick and sweet. In a recovery period when rehydration also is an issue, they should have advised a much bigger volume. If you add another 400 mL of skimmed or semi-skimmed milk, the drink will just taste great (I would have given a 4 out of 5).


Aptonia has got the macronutrients right. Also, they had the good idea to use milk proteins that usually taste relatively good rather than purified whey proteins that usually taste… well.. . interesting… Most important, I never had gut issues after drinking 700 mL of it. However, Aptonia doesn’t get a 5 because of the high amount of anti-oxydants added.

Overall, it’s 11/20 for the Aptonia Recovery Drink

(or 14/20 if you follow my way of preparing it!)

In short, with an appropriate mix of macronutrients, a nice chocolate flavor, and a good digestibility, this recovery drink has great potential. If you can tolerate the lousy packaging and adapt the mode of preparation, you’ll get a great value for the money!

As a final word, I need to say, like for all sports nutrition , that you can get all these nutrients from real food items.These sports nutrition products are just a ready-made, easy-to-carry-around option. There are lots of possible post-exercise snacks that would support recovery at least as well as all products on the market. And it’s way less boring over the long term! I’ll give you examples in a next article!

Thanks for reading! And stay tuned for more testing!


Dennis Kimetto of Kenya crosses the finish line in new world record time

(Boris Streubel/Bongarts/Getty Images)

Recently, Nike announced its plan to break the 2-hour marathon barrier in 2017. It is an audacious plan (some might say impossible), as it requires to reduce the actual record (2:02:57) by 2.5 %! But Nike is not the only player to work towards this crazy goal : Adidas also announced that they have been working on a similar project for 2 years. In addition, sub2hrs, a consortium of scientists and sports companies, has already claimed responsibility for some top-level performance, such as lthe near-2hr performance by K. Bekele during the last Berlin marathon (2:03:03).

Beyond the runners and their sponsors, breaking the 2-hour barrier is also a tremendous challenge for the exercise physiologists! Many areas of exercise science (biomechanics, metabolism, …) are impacted by this sub-2hour quest and sports nutrition will be a significant part of the equation.

In the next weeks, we will write a series of articles discussing how nutrition can help break the 2-hour marathon barrier. Today, let’s talk about the new secret drink that Bekele may have used in its last Berlin marathon.

EPISODE 1 : A new revolutionary drink?

During an endurance race, the ingestion of carbohydrates usually improves performance (check this article for the current guidelines). But are the more carbohydrates the better? Protocols with increasing carbohydrate intake have shown that their absorption and subsequent use as fuels are limited. Why is this?

First, our stomach tends to slowly release nutrient-containing drinks into our intestine instead of letting them flow through. Second, and there is still debate about this, it is possible that some carbohydrate transporters in our intestine (those who shuttle the sugars from the intestine to the blood) reach a maximal speed and could not keep up with very high carbohydrate concentrations.

1. Maurten and the hydrogels

A Swedish company, Maurten, claims it has found a way around some of these limitations : hydrogels! According to them, a hydrogel-based drink is emptied faster from the stomach than a normal sports drink. Is that really true? And is such a drink involved in Bekele’s stunning performance?


(a snapshot of the Maurten website)

First, what is a hydrogel? A hydrogel is a three-dimensional molecular network that can contain a lot of water. In this water-based gelly-like structure, it is possible to pack water-soluble molecules. These hydrogels have been used for example to package drugs and increase their lifetime in blood or increase their delivery. Now, imagine that, instead of therapeutic drugs, Maurten has packaged a lot of carbohydrates into a hydrogel, and that the hydrogel still is fluid enough so that you can drink it. Would this make it go faster through the stomach?

Well, the control of gastric emptying is a complex process, with many neuronal and hormonal influences. So, I won’t try try a theoretical answer but will focus on what has been tested. Old (but great!) studies have shown that the time of gastric emptying is highly dependent on the carbohydrate concentrations : the more carbs, the more the drink stays in the stomach! But they also have shown that osmolarity also plays a role. For the same carbohydrate concentration, low osmolarity drinks prepared with big polymers went faster through the stomach.

Wait, what is osmolarity? It is basically the number of molecules in a drink. We don’t think about it so much, but it is possible to achieve the same concentration, say 60 grams of carbohydrates / liter, with different types of carbohydrates. Indeed, If you use small single molecules, like glucose, you would need a lot of them to reach 60 grams, so the osmolarity will be HIGH. If you use, big, sweet polymers, like amylose or maltodextrins, you would need less molecules to reach 60 grams and the osmolarity will be LOW.

2. My bet on what a hydrogel drink can be

Back to Maurten, we can imagine that the hydrogels are entirely made of carbohydrates. Long polymers like amylose or pectin can easily form gels (the latter are used in fruit jams for example!). Interestingly, this hypothesis has been tested in 2000, by a group of UK researchers. And indeed, gastric emptying was faster in the gel-like drink!

So, although there is very very very limited information around the Maurten drink, here is my bet:

Maurten has formulated a hydrogel based on long carbohydrate polymers such as amylopectin. This gel/drink may go faster through the stomach, thus allowing to pack a lot of carbs in the drink and reduce tolerance issues.

UPDATE: Maurten revealed the main ingredients of the hydrogel drinks in an e-mail to its followers on March 6th 2017.

screen-shot-2017-03-08-at-11-39-38So : Maltodextrin, Fructose, Pectin, Sodium alginate and Sodium chloride. I wasn’t very far 🙂

The stuff that I haven’t seen coming is the fact that the drink is liquid at first but becomes a gel in the stomach, so at low pH. Clever… but I can’t really conceptualize how gastric emptying could be faster with a gel in the stomach… 

3. Field testing

In an interview available on the sub2rs website, Andrew Bosch, associate professor and exercise science at the University of Cape Town, and involved in the nutritional aspects of the sub2hrs project, revealed interesting practical details about the hydrogel drink.


Bosch acknowledges field testing of the drink, thus implying it is at an advanced production stage. “It’s a powder that’s mixed with water”, says Bosch, suggesting that it doesn’t require a specific processing that would make the use of the drink impractical.

It seems that the purpose of the field experiment was to test the upper limit of concentration that is tolerable by the runners. The scientists tested increasing concentrations of carbohydrate-containing hydrogels and Bosch confidently reports: “they didn’t get an upset stomach or feel uncomfortably full”.

Interestingly, this testing happened in Ethiopia, in a running group that involved Bekele as “the main athlete”. This clearly supports the idea that the hydrogel drinks already are used during major running events, including by Bekele himself during the last Berlin marathon.

4. Remaining questions

All of these theoretical and practical news sound great, but there are still lots of questions to be answered.

1/ Are these extra carbohydrates indeed absorbed? Increasing gastric emptying doesn’t mean that the carbohydrates will be absorbed by the intestine.

2/ Are these extra carbohydrates really used to fuel the exercising muscle?

and, most important:

3/ Does it lead to an increase in endurance performance?

Maybe Maurten has all the answers and keeps them secret. Maybe they don’t and they need to do their homework.

Anyway, I bet that independent research groups will challenge this hypothesis and I’m excited to see the results. I’m also very excited to try to make hydrogels in my kitchen : be sure that I will share my own hydrogel recipe very soon!! We can’t be sure that this new hydrogel drink will allow an elite runner to break the 2-hr barrier but we can be sure it will shake the sports drink market!


It is great to see how this crazy sub-2hr project fosters innovation in the field of sports nutrition! There is still a lot to explore in the field of exercise science and medicine and it is incredibly refreshing to re-discover that performance enhancement can be achieved without illegal doping. Yet, we may need to wait a long time before hydrogel drinks can be backed up by independent research! I’ll keep you posted!




In the « How To ? » section, we take the best of sport science and translate it into practical nutrition for endurance athletes.

Most of the time, nutrition is a very qualitative science : we are asked to eat a “healthy” diet, with “a bit of everything”. But when there is sports involved, quantification becomes necessary. Today, we will tackle the specific and crucial issue of nutrition during a race in a quantitative way. For the sake of time, we will limit the discussion to intense endurance exercise for up to, let’s say, the ironman distance.

There is a lot of old and new evidence indicating that nutrition during an intense endurance event is all about carbohydrates. When the duration increases and the intensity decreases, it’s a totally different topic. So, a much-needed discussion about ultra-endurance will come later (I swear)!

With that in mind, let’s do the maths and find out how much carbs are needed on race day! Let’s break things down by event duration.


a. Very short events (< 20 to 30 min):


Forget race nutrition strategy and run as fast as you can!

b. Short events (30 min to 1 h):

Rinse your mouth with (or drink) a carbohydrate-containing solution (no need to go higher than 30 g of carbs/h)

For a long time, we thought there would be no advantage of eating carbs in short duration events. If we have enough glycogen in our muscles to fuel such events, why would we need more exogenous carbohydrates?! But interestingly, studies have shown that if you rinse your mouth with a carbohydrate solution during short duration events (yes, just rinsing, drinking is not necessary), you will run faster. It is still unclear exactly why it’s the case. The current theory is that the brain normally prevents us to achieve our highest performance, probably to keep us from damaging our tissues and from in fine killing ourselves. A carbohydrate-sensing mechanism on the tongue may inform the brain that more energy is coming, and the brain may then allow us to unlock some more of our athletic potential.

A photo by Aidan Meyer.

Yes, you can also pour your sports drink all over your face and see if it sill works.

c. From 1 to 2 h:

30 to 60 g of carbs/h

Here, we are in the sports nutrition science “sweet spot”, where a lot of different types of sports drinks have been tested in interaction with different exercise modalities. Go ahead, it does improve performance compared to water alone.

d. Above 2 h:

up to 60g of carbs/h

90 g/h with a mix of glucose and fructose sources may be an option

Studies using carbohydrate sources providing glucose only (such as dextrose or maltodextrin) suggested that, above 60 grams of glucose per hour, the extra glucose ingested was not used to provide extra energy to the muscles. It was consequently considered as useless to drink more carbohydrates than this 60 g/h limit. The current hypothesis (lacking mechanistic support I have to say) is that the gut transporter that allows glucose to enter our body gets saturated. Knowing that fructose enters our body through another door than glucose, it has been suggested that we may overcome the 60 g/h barrier by adding a bit of fructose to the traditional glucose drinks. There is quite some literature around this idea, sometimes conflicting literature, but the bottom line is that it seems possible to increase the contribution of exogenous carbs (those we eat) to the energy supply to the muscles using this technique. Practically, this is done by drinking up to 90 g/h of a mix containing 2 glucose for 1 fructose (NB: saccharose contains one glucose for one fructose, some packages may even indicate the glucose:fructose ratio).



The frequency at which you drink or eat during a race is a key factor for a successful nutrition strategy. Two physiological processes play a role in this issue: 1/ the rate at which your stomach transfers food or fluids to your intestine (this is called “gastric emptying”) and 2/ the speed at which your intestine can take up the carbohydrates. During intense exercise, these 2 processes are particularly disturbed, because the increased blood perfusion in the muscles make the stomach and the intestine less likely to function properly.

To make a long story short, the key message is:

Eat or drink often (15-20 min), have small bites or sips

Studies have shown the superiority of this approach compared to ingesting larger amount of nutrients at bigger intervals. Thus, the “small and often” approaches reduces the likelihood of gastrointestinal distress, one of the biggest enemies of performance! Practically, I found it helpful to set a 20-min “nutrition” timer on my watch.

3. IN WHICH FORM (gel / drink / solid / …) ?



Some studies indicate that, at high intensity, solid food (ie bars, or real food items) may lead to more gut discomfort than a gel (with sufficient water) or a drink. For very intense events, this may even lead to a reduction in power output, probably by decreasing comfort and ease of exertion.

But, as often, this is clearly an issue of individual tolerance. So, here, the rule is:

Do whatever pleases your gut.

Test all your food during training sessions (at race pace) or B-races.

Of course, gels / drinks / bars bring a slightly different amount of carbs. You can keep in mind that:

  • a gel gives about 15 to 25 grams of carbs.
  • a drink usually contains 30 to 40 grams of carbs for each 500 mL.
  • a bar has around 20 to 40 grams of carbs (but very likely also other macronutrients)




Adaptations to extreme environmental conditions (heat, cold, altitude, …) are best achieved with acclimatization strategies. Nevertheless, little adaptations of the nutrition strategy on race day can help. When carbohydrates are provided with sports drinks, it is recommended to:

dilute or concentrate your sports drink based on your hydration needs

In other words, dilute your sports drink when it’s hot (because you will most likely drink a lot of it) or concentrate it more in a cold environment. A practical advice would be to use a powdered form of a sports drink and adjust the concentration yourself. Quantitatively, we can estimate that most sports drinks contain 60 to 70 grams of carbs / liter. So, dilute up to 30 g/L for ambient temperatures > 20°C and concentrate up to 80 to 90 g/L for cold races (< 10°C).


Nutrition, like any other elements of a race strategy, does not always go according to the plan. So, think of a plan B! Say, if you already feel gastrointestinal discomfort after 15 km in a marathon, be mentally prepared to switch to an alternative plan. For example, you may consider one of the following options (in this order):

  • Reduce the workload for your gut. Stop solid food and choose gels + water or sports drink.
  • Reduce the concentrations of your sports drink, maybe by grabbing both water and sports drink at the next aid station and mixing them.
  • Give your gut a brief rest. Increase the gap between your nutrition moments to 30-40 minutes (instead of 15-20 min).


1/ try and plan everything before race day

2/ the longer the race the more carbs per hour (with the upper limit of 90 g / h)

3/ the more intense the race the more it is difficult for you gut, so go for fluids.

4/ modify your nutrition plan based on the race conditions and be ready to move to plan B!

To conclude, it is important to highlight that we only talked here about race day nutrition. There are now fascinating new developments concerning optimal nutrition to trigger training adaptations. These new diets notably experiment with very low carbohydrate intake, which is clearly in contrast with the high carbohydrate intake needed on race day. More on that paradox in a future article!




It’s post-holidays season and time to get back out for more adventures! After all the sweets you probably had for Christmas, here is a perfect transition to sports nutrition: sports waffles full of honey!


 1/ The Honey Stinger company:

Honey Stinger is a Colorado-based company with a pretty long history of honey products. In the 1950s, Luella and Ralph Gambler, both beekeepers, started to brainstorm around the idea of a honey-based energy bar. They also packaged honey in small pouches for athletes. Although the products had some success within the local sports community, it wasn’t before the 2000s that the company really started to exist in the market of energy foods.

Well, honey and waffles… all that sounds good! Let’s dive into it.


 2/ The product and its category:

The segment of sport waffles is slowly growing, with big players like PowerBar or GU. I don’t have the data but it doesn’t seem like the segment is exploding neither. Rather, it seems like waffles have found their niche among the bars, gels, chews, beans, etc.

On one hand, I like to see sports nutrition products that look like real food items: it is especially great for long endurance workouts, when you might be bored of gels and sports drinks. On the other hand, though, it is often a challenge to pack some adequate sports nutrition into a food item that people already know and love, without compromising on the nutrition parts (if the product tastes great, it’s often because it has quite some fat…). Let’s see how Honey Stinger has dealt with this.


3/ Unboxing:

The first thing that came to my mind when I saw the waffles for the first time was: YAY, STROOPWAFELS! If you don’t know what I’m talking about, I mean the Dutch waffles made of two thin layers of waffles filled with a thick syrup in the middle. You should try them, it’s a real delight.
outhoneyAfter this first good impression, I realized that the waffles also have the major annoying drawbacks of stroopwafels: they break (you can see the lines of fracture on the picture above) and make crumbs… Like… lots of crumbs.


I stored these waffles on a shelf for a few months, so they might have dried a little, thus amplifying the crumb problem. But these waffles were still months away from the expiry date (actually 4 months before the “best before” date).

On my (non-really calibrated) scale, the waffle itself comes at a perfect 30g, as it says on the package.


+ about 2 full grams of crumbs (that you will most likely loose if you’re out running or riding your bike).

scalehoneycrumblesThen, I spent a few minutes removing the crumbs and had a look at the inside.


As you can see on the picture, the structure of the waffles is similar to the Stroopwafels! Two thin layers of waffles filled with what I believe is a honey-based syrup.


Looking closer, it looks like the syrup has diffused through the waffles, which made them a little more sticky than they probably should be.


4/ Tasting:

I can’t say whether you will like the product or not. But I can try to describe the texture and flavor as objectively as possible. So, if my “objective” description matches what you may like, go buy the product and reach out on social media to give your opinion!


The best description I can give of these waffles in terms of appearance and texture is: “half-dried honey stroopwafels “.  They are a little sticky on the fingers and quite sandy in mouth. Despite that, they are still relatively soft and easy to chew while running.


In terms of taste, you get what you expect: a strong honey flavor and a high sweet intensity. All other flavors are only moderately present.


5/ Situation test:

I took the waffles with me on a few occasions, including two cross-country skiing sessions in Zurich. It’s quite rare that we could cross-country ski in the city. I got very excited and looped the local forest over and over. Anyway, not the topic…


It confirmed the things I started to see in my kitchen.

– BREAKS when you have it in your pocket, producing even more of the crumbs. The consequence of this is that you may want to eat the whole waffle at once. Putting it back into the open pouch and into your pocket would most likely create a mess. So, wait until you are a little hungry!

– TASTY! And very satisfying when you are craving for sugar.

– HARD WHEN COLD. Another common point with the Stroopwafels is that they get hard when they are cold. This is to be expected given the sugary syrup used for the filling. Traditionally, the Dutch place their waffles over a cup of tea or coffee to soften the syrup. Consider doing that if you are out with a thermos of tea or alike.


After a few hours in the fridge (or in your pocket while skiing), the waffles were still chewable though, this is nothing like the Clif bars.


6/ Nutrition:

As we could expect, the waffles are extremely dense in carbohydrates.. but also rich in fat… That’s the problem I referred to in the introduction of this article. When you want to produce waffles, and especially tasty waffles, it’s hard to avoid using quite some fat. Otherwise, you would most likely produce something that tastes funny for a waffle.

Here are the nutritional values for a 30 g waffle and for 100 g (it makes it easier to compare with other products).

   / 1 waffle (30 g)  /100 g
 Energy (kcal)  150  500
 Carbohydrate (g) / Sugar (g)  21 / 11  70 / 37
 Fat (g) / Saturated fat (g)  7 / 3  23 / 10
Protein (g)  1 3.3
Fiber (g)  1 7.4
Salt (mg)  ?  ?
Sodium (mg)  60  198
Calcium (mg)  0  0
Magnesium (mg)  ?  ?
Potassium (mg)  ?  ?

I was surprised that the carbohydrates don’t seem to come in majority from honey. I can’t really say that for sure, but “rice syrup” and “cane sugar” came before “honey” in the list of ingredients. I may understand that honey may need to be mixed with a thicker syrup to stay in the waffles but it would be nice to know why honey is not the main sugary ingredient here.





The waffles consistently produced a lot of crumbs, so you loose some while opening the pouch. And  you can’t put it back into your pocket without making a mess. They are a little sticky and gets hard when cold.  The size, though, is ideal for a short snack into a long run.


Even stored on a shelf, my waffles were a little broken. That’s definitely a quality issue. Overall, it’s a solid product that looks good.


I’m really happy with the taste. It’s close to what you would expect from a Stroopwafel-like product… and I love Stroopwafels (so big bias here!) 🙂



The flipside of a great taste usually is a higher-than-normal fat content. But the waffles are rich in carbohydrates and I had no gut issues.

Overall, it’s 13/20 for the Honey Stinger Waffles!

In short, with a 150 kcal / waffle, a relatively high fat content, and the form of a real food item, these waffles are good candidate to fuel long runs, or even ultras.

Thanks for reading! And stay tuned for more testing!


In “The science!”, I discuss the scientific evidence available around a hot topic and present some recent exciting new studies in the field of sports nutrition and metabolism.

These discussions reflect my own understanding of a scientific topic and are not peer-reviewed scientific articles. If you think my views are wrong, I would be very grateful if you could yell at me in the comment section below or via the contact form. Because that’s what science is all about: discussing, making mistakes and constantly improving (and a bit of yelling at each other sometimes).

Sports physiology textbooks are very clear: during endurance exercise, the relevant fuels are carbohydrate (mostly from your muscle glycogen) and fat (mostly from your intramuscular triglycerides and plasma free fatty acids).

That was it… and for a long time…

And then, sports scientists started to talk about ketone bodies: a good old fuel that is produced during starvation and hence, seemed to be irrelevant for the field of sports energetics…

In this post, I’ll take you through the journey that brought ketone bodies from the status of useless sports fuel to the most trendy sports drink ever. This journey includes starvation, athletes running to the toilets and a touch of biochemistry. Still in? GREAT!

1. Ketone bo… what?


!!Biochemistry alert!!! (jump to the next paragraph if you have been traumatized at school by your biochemistry professor)

In a normal situation, glycolysis (via pyruvate) or the beta-oxidation of fatty acids lead to the production of acetyl-coA: the latter feeds the TCA aka Krebs cycle, which produces everything you need for the mitochondria to finish the work (produce ATP through the respiratory chain).

During starvation though (ie when carbohydrate availability is limited, insulin is low, glucagon is high, glycogen is exhausted), the liver converts some of its acetyl-coA into ketone bodies. These molecules are then released into the bloodstream and bear the great names of acetoacetate (AcAc), beta-hydroxybutyrate (we’ll say BHB), plus their breakdown products acetone.

Interestingly, the muscles, the brain and the heart are pretty good at taking up circulating ketone bodies and convert them back to acetyl-coA to oxidize them (which the liver can’t do because it lacks the converting enzyme).


Overall, ketone body metabolism is an organ crosstalk that, in the conditions of stringent energy deficit, provides an alternative, readily oxidizable substrate to the brain and peripheral organs. This has the double advantage to satisfy the energy requirements of these organs and to spare glucose reserves, two effects that will eventually prolong life.


!!!Biochemistry alert over!!! (traumatized people may read again)

2. Ketosis and the (difficult) relationship with exercise

So what does ketosis (high levels of ketone bodies in the plasma) have to do with exercise performance?

A/ Prolonged intense exercise stimulates ketone body production and post-exercise ketosis has been repetitively documented.

The exercise-induced ketosis, in some ways, resembles the starvation-induced ketosis: the progressive exhaustion of glycogen stores induces ketone body production, which in turn provides readily oxidizable substrates to the muscle and spares whatever is left from the glycogen. In other words, it can be seen as an evolutionary-relevant mechanism to prolong physical exercise. There is, however, ample evidence to suggest that an adequate nutrition strategy (CHO intake during exercise) positively impact endurance performance and endurance capacity while preventing or postponing exercise-induced ketosis.

B/ Dietary interventions, in the form of low carb high fat “ketogenic” diets, and their impact on performance, are debatable (that would be a whole other article).

In a nutshell, it is rather clear that low carbohydrate availability will negatively impact high intensity endurance performance. However, strategies that combine training in low carb conditions while competing with repleted glycogen seem to enhance submaximal exercise performance, via the upregulation of muscle fatty acid oxidation. Whether this is the result of the ketosis itself, or an adaptation to the high-fat content of the diet, remains unclear. The potential downside would be that a low carb diet reduces the capacity to oxidize carbohydrate, thereby limiting performance in a high glycolytic contexts (final sprinting, pace changes, hill running…). To summarize, a well-planned nutritional ketosis during training may positively impact submaximal exercise performance but it’s clearly not the magic bullet to improve endurance performance.

At this point, it’s clear that ketone bodies may be great oxidizable substrates for the muscles. But their main problem is that they are endogenously produced in a starvation-like context, which is not favorable to endurance performance. So, what about an exogenous source of ketone bodies? This should combine the best of both worlds (ketosis with high glucose stores)?

3. Drinking ketone bodies… not as easy as it sounds

To provide ketone bodies as an exogenous substrate for the muscles, you just need to drink it…

Ketone drink illustration

Yeah… no… not that easy…

First, there is an issue with the dose. We’re not talking about a bioactive compound in the microgram range here, but about an oxidizable substrate for the muscle. So, realistically, doses in the range of several hundreds of milligrams per kg are needed. For a 70 kg man, 500 mg/kg would mean that 35g should be given, for example, in a 500 mL drink. To compare with carbohydrates, you will find the same concentration of glucose in a typical sports drink (60-70 g/L).

In relation to that, there seems to be a problem with the taste of ketone bodies-based drinks. Although I haven’t tried myself, I keep reading blogs of self-experimenters describing the taste as “categorically horrible”, and close to what they “imagine jet fuel would taste” (these were BHB-monoesters and AcAc-diesters).

Moreover, gastrointestinal (GI) tolerance may be problematic when delivering ketone bodies at higher doses. Recent studies, however, report the production of ketone body esters that seem to partially resolve the taste and GI tolerance issues. (I say “seem” because the scientific article did not directly comment on palatability and still showed a great number of GI-related adverse events at higher doses – Clarke et al., 2012)

4. The impact of ketone esters on exercise metabolism and performance (new study!)

Recently, a study published in the prestigious journal Cell Metabolism (August 2016) provided the first solid evidence that ketone esters can indeed improve endurance performance.


At first, I saw that some of the authors actually are members of “UK sport” or orbiting around the Sky pro cycling team. Giving the time it takes to conduct a scientific study and to publish it in a high impact journal, team Sky and others probably had their first sips of ketone drinks 3-5 years ago.

And well … do you remember … rumors of drinks with ketone bodies on the TdF 2015, with Froome denying using ketones…

“I had to google it to find out what it was”, C. Froome

I find it hard to believe now. Maybe he didn’t use it but there were definitely Sky-related individuals involved in that scientific study in 2015. Anyway… back to science…

In the article, Cox and colleagues first studied the effect of ketone esters (provided as a drink) on plasma and muscle metabolites during a single short bout of cycling (45-60 minutes). The participants were given a ketone ester drink which, compared to an isocaloric carbohydrate drink, increased the plasma levels of ketone bodies and led to an increased oxidation of ketone bodies by the muscles during exercise. The authors estimated the contribution of ketone esters to 16-18% of O2 consumption during exercise at 40 to 70% Wmax.

Interestingly, in the muscle of the athletes that drank the ketone esters, glucose was spared during exercise via the reduction of glycolysis, which was also evidenced by a reduction in plasma lactate.

During a longer exercise bout (2h at 70% VO2max), the authors could also show that the two intramuscular forms of fuel storage were impacted by the ingestion of ketone esters. Indeed, after exercise, subjects that drank ketone esters had less intramuscular triglycerides and more glycogen left in their muscles.

Logically, the authors sought to test the effects of their new drinks on performance. They set up a protocol that included a 1 h steady state at 75% Wmax followed by a 30 min time trial (TT) on the bike. Ingestion of the ketone ester + CHO drink resulted in a 2% average increase in performance (around 400 m further) compared to CHO alone.

All of these impressive results were consistent with the ideas that:

a/ ketone esters can be oxidized at high levels by the muscles. The results presented here suggest that the oxidation of ketone bodies is prioritized over that of carbohydrates or fat, even at an exercise intensity that should be highly glycolytic. That is very interesting, because in a starvation state (with low glycogen), ketone oxidation by the muscle was consistently reported to be extremely low. So, the difference is that here, a high energy demand in the glycogen-repleted muscles coexists with high ketone body levels, leading to a high level of ketone bodies oxidation.

b/ beyond their own oxidation, ketone esters alter fuel selection, reducing glycolysis and (maybe) increasing fatty acid oxidation.
Because ketone bodies can be rapidly converted back to acetyl-coA, I would speculate that the changes in acetylcoA/coA ratio induced by ketone conversion probably is the molecular mechanism that inhibits glycolysis. In addition, because the acetyl-coA flux is provided rapidly by ketone bodies, this eases the reliance on pyruvate and restores fatty acid oxidation.

c/ these changes in muscle metabolism can enhance performance in a time trial cycling exercise bout. And that’s probably where the paper lacks a lot of speculations about the mechanisms. Here is what I think; after 1h of steady state at 75% Wmax, the muscle glycogen concentrations in the control group start to slightly drop sometimes in the middle of the 30 min time trial, whereas the ketone drinkers had a permanent supply of ketones to oxidize and therefore, relied less on their glycogen stores. Unfortunately, we don’t have the gas exchange during the time trial, but I would bet that, towards the end of it, the controls slowly started to switch to fatty acid oxidation, thus reducing their power output. In other words, I’m not sure that the effects on performance would still hold up if the time trial wasn’t preceeded by a glycogen-depleting steady state.

Conclusions and some thoughts

There are now several studies that shows it is possible to deliver ketone bodies at high doses using a ketone ester, and one study that shows the effect on muscle metabolism and performance. As good as the science is in these papers, there is still no large-scale evidence to recommend drinking ketone bodies while riding a bike. There is just not enough studies around to pinpoint with precision where the benefits might be, for which exercise modality and for which athlete populations (these were highly trained -pro?- cyclists). In addition, studies on the metabolic adaptations to a chronic exposure to ketone esters drinks would also need to be conducted.

The practical issues of taste or GI tolerance that are reported here and there will probably slow down the development of ketone drinks (at least by serious nutrition brands). But the drink used in the Cell metabolism study is supposed to be commercially available within the year, via an Oxford-university spinoff. I can’t wait to try… and report to you!

Finally, these drinks start to spread within the sports community; so the question whether it is doping or not doping will arise pretty fast. Indeed, like a lot of performance-enhancing drugs, ketone bodies are endogenous molecules, whose exogenous administration may increase performance (think about EPO or testosterone). It will be interesting to watch how antidoping agencies handle the issue. Stay tuned… The ketone debate is still on!