 The use of exogenous ketones has been getting a lot of buzz lately, especially since they're reportedly being used by world tour teams like Yumbo Visma, the team that won both the yellow and green jersey at this year's Tour de France. This is obviously quite an endorsement, but, and I know this is going to be hard for some people to believe, just because someone fast does something does not necessarily mean that that thing will make you fast. As always, we're going to be taking a look at what the science has to say about the topic at hand, and on the chopping block today is ketones. Are ketones just another fad or marketing gimmick like so many supplements before them, or are there some real benefits to be had by taking them both for performance and recovery? I'll get into all of that, but before I do, I want to ensure you that this is not a sponsored video. Ahem. What the f**k dude, Hyper Game Beast Mode just came out with a new ketone drink. Are you seriously not going to let me plug it? I'm not being paid, and this is also not a review of my own personal experience using ketones. Because to be quite honest, a lot of these supplements, including the ones that actually work, have such a small effect that if somebody is telling you that they can feel the difference when they use it, it's probably just the placebo effect. Let's start by discussing what ketones are and what exactly they do. Endogenous ketone bodies are derived from fatty acids in the liver and transported to peripheral tissues where they are oxidized for energy and have the potential to serve as an alternative substrate to carbohydrate during endurance exercise. Essentially, ketones are another source of fuel that your body can use for energy other than carbohydrates. Ketones are often associated with the ketogenic diet, which involves eating a high amount of fat and a low amount of carbohydrates. After a ketogenic state when your body is deprived of glucose, ketone bodies are produced to replace glucose as the primary fuel. Now it may be at this point that you say, wait a minute, I thought that the ketogenic diet was bad for exercise performance and you need carbs to ride fast. And research definitely backs this up. The ketogenic diet simply doesn't seem to hold up in the literature. Whenever I bash the ketogenic diet on this channel, which has been a number of times at this point, the keto fans come out of the woodwork to tell me I'm an idiot. I look forward to your comments on this video. I don't have time to get into the weeds on the ketogenic diet in this video, but if you're still unconvinced or you just want to learn more, then I've left links to my keto videos down in the description below. The failure of the ketogenic diet, however, is by no means a nail in the coffin for ketone supplements. The problem with the ketogenic diet is that in order to elevate your ketone levels, you have to severely restrict carbohydrates, which, surprise, surprise, hurts your performance. But what if there was a way to not restrict carbohydrates and still get those elevated ketone levels? Could this be the best of both worlds? During a race or a hard ride, would you be able to spare your body stored carbohydrates as it uses ketones instead and then use those carbohydrates later on when you really need them, like in a final sprint or an attack? This is one of the theories behind taking ketone supplements. Certainly makes sense in principle, but what does the research have to say? First of all, it does appear that supplemental ketones can be used as a fuel source, as demonstrated by this study which had subjects consume carbs, ketones, or fat before a one-hour cycling test. When compared to ketone levels taken at rest, it appears the body is in fact using ketones to fuel the one-hour bike ride. Now, it's all well and good that the body is actually using these ketones for energy, but let's remind ourselves of why we're taking this thing in the first place. It's to perform better on the bike. This is the same argument I use when keto diet fans show me a study where ketosis allowed athletes to use more fat for fuel as if I didn't cite that very study in the video that they just watched. Okay great, keto athletes use more fat, but why should I care? The real question is, did it actually make them go faster? Cycling is not a contest to see who can burn the fewest carbs, it's a race to see who can cross the finish line first. You guys sensing a bit of anger? I think the keto people finally got to him. Thankfully, the previously mentioned study on ketone supplements did test for this so we don't have to speculate. The study consisted of a one-hour submax ride followed by a 30-minute time trial. This kind of test simulates what you might see in a race where you're hiding in the peloton all day until the final climb. And what they found was that those who consumed both ketones and carbs did in fact perform better than those who consumed carbohydrates only. This does look promising, however there's a detail of the study that I do take issue with and it's that these tests were performed after an overnight fast. Sure the subjects consumed carbs or carbs plus ketones right before the test, but this isn't exactly what I would call a pre-race breakfast and this could certainly skew the results in favor of ketones, seeing as the subjects had reduced glycogen or stored carbohydrates from the get-go. I gotta say, it's very weird to me that the researchers would even set up the study this way. It's almost as if they were trying to design a study that would, oh, oh I see. That being said, this test was only an hour and a half long and a lot of bike races are a lot longer than that. Having reduced glycogen stores at the end of a bike race is actually fairly common, so this could be a point in favor of ketones. This study did increase the interest in ketones as a potential performance enhancer. However, we never want to rely on just one study and unfortunately further research looks less promising. For example, this study which also looked at ketones and time trial performance actually had subjects consume a carbohydrate breakfast before testing. Groundbreaking stuff, I know. The subjects then consumed either a ketone diaster or a placebo drink 30 minutes before the test and this is what they found. Slower times and lower power outputs when the subjects took ketones. Given the previous study, this may seem unexpected. What's the reason for these results? Gut discomfort and intolerance among the participants with symptoms ranging from mild to severe. And this is not the only study coming to this conclusion. Other studies have found similar results. There are potential explanations for this discrepancy in results though, and the first one is the type of ketone supplements that were used. This systematic review on ketone supplementation found that of 16 studies identified, 3 showed positive results, 10 showed null results, and 3 showed negative effects of ketones. And a big part of that may be the concentration and type of supplement used. Consuming ketone monowesters seems to result in the highest concentration. What ketone diesters, ketone salts, ketone precursors, or even consuming ketone monowesters under fed conditions don't. Alright, just look focused and not. That way he'll think that you know what the hell any of those words mean. Basically, the type of ketone supplement that you choose and when you take it makes a difference. You want to go with ketone monowesters and consume them under fasting conditions. Also, there is research that suggests that using bicarbonate in conjunction with ketones may unlock the potential performance benefits of ketones. There's also another potential confounding factor here, which is the type of test used. Remember that the purported benefit of ketones is to preserve glycogen, so in long, low-intensity tests they may perform better while in shorter, higher-intensity tests the impaired glycogen flux may actually be detrimental. Whether or not ketones will work for you could very likely be dependent on the kind of racing that you do. If you're an ultra-endurance racer who's depleting your glycogen stores, then they may be beneficial. However, if you're doing 45-minute cyclocross races with a lot of punchy efforts, eh, probably not. When we take a step back and look at the balance of evidence on how ketones affect performance, the results look mixed at best. This mixed evidence led this review to state that there's insufficient evidence to conclude recommendation of consuming ketone supplements on physical performance, and this meta-analysis comes to the same conclusion. However, this is not the end of the ketone discussion. Up until this point, we've been talking about how ketones affect performance, but as with many supplements, there's a second question, which is how do they affect recovery? And this may be the area where ketones start to shine. This study on ketone supplementation looked at just that. They had subjects undergo a three-week training period while consuming either ketones or a control drink. At the end of the three weeks, they tested the subject's 30-minute power at the end of a two-hour ride. So the subjects would be going into this final session fatigued after three weeks of hard training, and then be even more depleted on top of that before the crucial 30-minute test. If ketones had in fact improved the recovery in these subjects, then they should perform better in this final test. And this is exactly what they found. The subjects performed better in the 30-minute test and saw less suppression in their heart rate over the training period. Certainly promising results, but one critique that I do have is that there appears to be a substantial difference in the number of calories that the two groups took in during the training period. We can see that the ketone group was taking in significantly more calories than the control group. Now, ketones may actually be the reason for this, as their effects on the appetite hormones would suggest an increase in appetite. This increase in appetite could certainly be a benefit to taking ketones during a hard training period, but it's also a confounding factor. Did the subjects recover better because they were eating more or because of the ketones themselves? If you had both groups consumed the same number of calories, would the results be different? Unfortunately, we don't have that study, but there are other studies that show positive effects of ketones on recovery. For example, this study showed an increase in muscle glycogen synthesis. That being said, the data right now is limited. There just simply aren't a lot of studies on how ketones affect recovery. This review on the matter agrees, however, the current limited evidence would suggest that there are potential benefits to be had. I do have to mention, though, that one of the authors of this study is the research lead for HVMN, which is a company that sells ketone drinks. Ugh, freaking corporate shills. My final take on ketones given the research that we currently have is that it probably won't help for the majority of race applications if it's simply taken right before the race. However, I will be on the lookout for any research on ketones and ultra endurance athletes. As far as recovery goes, there are some very promising initial findings. So again, this is an area of research to keep an eye on. Maybe the world tour teams have some information that we don't have, and this could be a game changer for recovery. Or maybe not. Well, the Yumbo Visma guys are faster than you are, so... I'm not going to say conclusively whether ketones help with recovery or not right now until more research comes in. This may call for a part two in the near future. Thanks for watching. If you're interested in coaching, follow the link below. I also have training plans available, also linked below. If you enjoyed this video, be sure to give it a like, subscribe, and share this video with your cycling friends. I'll see you in the next one.