Episode 88 - Can Chocolate Improve Endurance Sports Performance?

Can Chocolate Improve Endurance Sports Performance?

Chocolate is delicious. Amen. While it is high in calories and sugar, dark chocolate in particular also contains a number of beneficial compounds that may have positive effects on exercise performance.

One of the primary compounds found in chocolate is cocoa. Cocoa is rich in a group of compounds called flavanols, which have been shown to have a number of potential health benefits. Flavanols can improve blood flow, which in turn improves cardiovascular function. They are rich in antioxidants, which help to reduce inflammation after exercise. They can also help improve insulin sensitivity and cognitive function.

Several studies have investigated the effects of chocolate consumption on exercise performance. One study, published in 2015 in the Journal of the International Society of Sports Nutrition found that consuming dark chocolate for 14 days improved cyclists' performance in a time trial. Let’s take a closer look…

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Patel, R. K., Brouner, J. & Spendiff, O. 2015. Dark chocolate supplementation reduces the oxygen cost of moderate-intensity cycling. Journal of the International Society of Sports Nutrition, 12, 1-8.

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Episode Transcription

Episode 88: Can Chocolate Improve Endurance Sports Performance?

Taryn Richardson  00:00

Welcome to the Triathlon Nutrition Academy podcast. The show designed to serve you up evidence-based sports nutrition advice from the experts. Hi, I'm your host Taryn, Accredited Practicing Dietitian, Advanced Sports Dietitian and founder of Dietitian Approved. Listen as I break down the latest evidence to give you practical, easy-to-digest strategies to train hard, recover faster and perform at your best. You have so much potential, and I want to help you unlock that with the power of nutrition. Let's get into it.

Taryn Richardson  00:36

It's the Easter long weekend and what better time to talk about chocolate and sports performance. But before we do, if you've got a little bit of time over the weekend, I want you to go and grab my Triathlon Nutrition Checklist. It's a 50 step checklist to triathlon nutrition mastery. So go and get that for FREE. It's at dietitianapproved.com/checklist and see how you're going with your triathlon nutrition. Have you got a fair bit of room for improvement? Or are you close to mastery? Spend your downtime this weekend seeing where you sit in the scheme of triathlon nutrition. Alright, let's get into it.

Taryn Richardson  01:22

You wouldn't expect me to be talking about chocolate on a triathlon nutrition podcast. But hey, here we are. I actually wrote a blog on this topic back in 2016 because a paper came out in 2015 exploring the idea of chocolate and performance. So I want to give it a bit of a resurgence because you probably haven't read it. It's in the deep archives on my website. But I think we can all agree that chocolate is pretty delicious. I don't know many people that don't like chocolate. And while it's high in calories and sugar, dark chocolate in particular also contains a number of beneficial compounds that may have a positive effect on exercise performance.

Taryn Richardson  02:03

One of the primary compounds found in chocolate is cocoa. And cocoa is rich in a group of compounds called flavanols, which have been shown to have a number of potential health benefits including improving our blood flow, which improves our cardiovascular function. It's rich in antioxidants, which helps to reduce inflammation after exercise. It can help improve insulin sensitivity and improve cognitive function, so our brain function. But sidenote, while cocoa is rich in flavanols, so too have fruits and vegetables, right? Just throwing that out there. So I'm not suggesting you eat chocolate to get flavanols if that's what you just heard, that's not what I said.

Taryn Richardson  02:44

But there's been several studies that have investigated the effects of chocolate consumption on performance. And the one study that I want to talk about today was published in 2015, in the Journal of the International Society of Sports Nutrition. And they found that consuming dark chocolate for 14 days improved cyclist's performance time trial - like win! So it was a group of nine moderately trained cyclists, so not elite level cyclists. We're talking about sort of age group athletes here. They were put through their paces in the lab and their baseline VO2 Max was measured before completing a 20 minute ride at 80% of their gas exchange threshold followed by a two minute all out time trial - balls to the walls, full gas. In a crossover design, they then consumed 40 grams of either the flavanol rich dark chocolate, or flavonol deficient white chocolate for two weeks before repeating the exercise testing again. So after a seven day washout period where they don't do anything, they then crossed over to the other arm, so either white or dark. And then repeated 14 days of the chocolate supplementation, so white or dark. And then repeated the testing again. Are you with me?

Taryn Richardson  04:03

So what did they find? The researchers found that dark chocolate consumption resulted in a 17% increase in the distance covered in that two minute time trial compared to baseline. And that was about 300 metres and a 13% increase compared to the white chocolate trial of about 200 metres difference. The dark chocolate supplementation also increased their gas exchange threshold by 21% from baseline and was 11% higher compared to white chocolate. Now there was no difference between the groups in the 20 minute moderate intensity cycle - their heart rate, blood pressure or blood lactate.

Taryn Richardson  04:45

So it seems that the dark chocolate or the flavanols seem to act in a similar way to beetroot juice, but through different mechanisms. Now beetroot juice is high in nitrates which convert to nitric oxide in the body and that helps to reduce the oxygen cost of exercise when it's sub maximal. If you want to dive a bit deeper into nitrate and beetroot juice, I have written a blog on this topic as well. I'll link it in the show notes if you do want to read about that. So the flavanols found in dark chocolate appear to increase nitric oxide bioavailability. Are you still with me?

Taryn Richardson  05:22

So let's put our critical thinking hats on for a minute. And I want to talk you through some of the things that I think about when I read a study like this, and then how to apply that practically. Because that's my superpower - trying to translate deep science into something that's practical and useful that you can understand and implement. So a couple of things, you can't effectively blind the cyclists in this trial to what arm of the research they're in. Obviously, they're going to be able to tell if they're being supplemented with a white chocolate versus a dark. So maybe there's a placebo effect, if they're thinking that dark chocolate is going to enhance their performance. There is something called the placebo effect where you think you're going to do better, and so therefore you do better.

Taryn Richardson  06:07

It was also a very small sample size, like N=9, nine people. That is a very small study. And so it'd be really hard to extrapolate those results to a wider population. The cyclists were regular punters. Yes, they had a healthy weight range. Their BMI was 23.75 to 24.55 (so they're far from elite athletes), with a VO2 Max values that are only sort of 41.9 plus or minus 5.4 mls per kilo per minute. So to put that into context, a typical elite cyclist's VO2 Max would roughly sit somewhere around 80 to 90 mls per kilo per minute, so double that. If you dive into the methods, their diet was controlled in the 24 hours preceding the exercise testing. And that's it. So there's lots of confounding food choices that could have actually affected the results like nitrate concentration, or carbohydrate quality of the diet or caffeine or anything like that.

Taryn Richardson  07:11

Dark chocolate also has a small amount of caffeine. And we know that caffeine is a very well established performance enhancing supplement. And so maybe the effects are actually because of the caffeine and not necessarily the flavanols. And on that, the flavonol concentration of the chocolate was never specifically tested. So we can't draw solid conclusions to say that the results was based on the flavonol explicitly. So don't take click baity headlines as evidence that something is good for us without actually diving into the nitty gritty of what the paper is and how they did it.

Taryn Richardson  07:53

So the study, which is a pretty cool study, honestly. It's only small but it definitely shows a bit of merit. And I would suggest warrants some further research in that area. Anyone put their hand up for doing some chocolate and time trial research? And you know, at the end of the day, what harm can come from consuming 40 grams of dark chocolate each day, right? Yes, it's worth noting that chocolate is high in calories, it's high in sugar, it's high in fat, and it doesn't have a lot of nutritional value.

Taryn Richardson  08:23

So I'm not suggesting you start adding it as a performance enhancing supplement - that's not what I'm saying, even if it is maybe what you're hearing. But there's no reason why you couldn't include maybe 40 grams a day. And that is ... 40 grams is only about two or three squares. It's not a couple of rows, it's not a whole block, it's just a square or two, so small portions. And we're looking for flavanol rich chocolate, so the dark chocolate varieties. Because not all chocolate is created equal. Have a look at the packet next time you buy your regular chocolate. I'm not saying start but when you buy your regular chocolate, have a look and choose something that is at least 70% cocoa solids to ensure you're getting that highest concentration of flavanols.

Taryn Richardson  09:39

So, move over coconut oil. We don't like you. Beetroot, dark chocolate is where it's at. You heard it here first. If anyone starts that and creates that as a performance enhancing supplement, I'm claiming royalties. If you want to dive into that paper, I'll link it in the show notes so you can read all of the details. But have a great Easter long weekend. Eat some chocolate. Just do it mindfully and if you have the choice, the darker, the better.

Taryn Richardson  15:56

Thanks for joining me for this episode of the Triathlon Nutrition Academy podcast. I would love to hear from you. If you have any questions or want to share with me what you've learned, email me at [email protected]. You can also spread the word by leaving me a review and taking a screenshot of you listening to the show. Don't forget to tag me on social media, @dietitian.approved, so I can give you a shout out, too. If you want to learn more about what we do, head to dietitianapproved.com. And if you want to learn more about the Triathlon Nutrition Academy program, head to dietitianapproved.com/academy. Thanks for joining me and I look forward to helping you smashed in the fourth leg - nutrition! 

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