Damaging Myths About Dietary Carbohydrates: Part 3


Check out Part 1 and Part 2 (links open in a new tab).

Defending something that is wrongly accused of having malicious effects on health and wellbeing is definitely liberating.

Carbohydrates continue to be the target of many diet gurus nowadays, often for reasons that are completely unfounded and blatantly incorrect. So, to finish off this series, I’m going to address two more damaging myths about dietary carbohydrates, and hopefully provide some clarity for those who continue to be confused about the topic of these controversial, nutritious little buggers.

You Don’t Need Carbohydrates to Perform at a High Level

When I first began researching nutrition and fitness, I was an athlete looking for the most proven methods I could use to improve my performance. While there is a ton of conflicting data on the topic of performance enhancement via nutrition, one thing was pretty clear: athletes need sufficient energy. Specifically, the message was that athletes need carbohydrates.

Once thought to be rock solid fact, the idea that athletes need carbohydrates to perform at a high level has been challenged repeatedly by those who invest in low carbohydrate superiority. However, it seems that the research cited in favor of low carbohydrate performance is far from solid. Also, as somewhat of an anecdote: the large majority of high level professional athletes do not consume a low carbohydrate diet. These athletes rely on their performance for their own well-being and often that of their families, so testing out an unproven and shaky method such as low carbohydrate diets is out of the question. They don’t have time to speculate and experiment, they must perform at a high level at all times, and they do so by fueling their body optimally with a carbohydrate heavy diet.

So let’s take a look at some of the research commonly cited by those who advocate low carbohydrate dieting as a means of improving athletic performance, and afterwards, compare it to the research on the dietary habits of  some of the highest performing athletes in the world.

Two of the more popular and highly regarded researchers among the low carbohydrate community are Jeff Volek and Stephen Phinney, both of whom put a lot of focus into the intricacies low carbohydrate performance. In fact, they wrote a book titled The Art and Science of Low Carbohydrate Performance, so it’s quite clear where their expertise lies. Admittedly, I have not read the book so I will not be addressing claims directly from there, but rather from research they have conducted.

Low Carb Diets to Improve Performance: An Effective Tool or Complete Hogwash?

A study done by Phinney et al in 1983 on well-trained cyclists concluded that “aerobic endurance exercise by well-trained cyclists was not compromised by four weeks of ketosis” (1). Well that’s that. A ketogenic diet did not ruin the performance of the cyclists, therefore it’s a viable option, right? Ehhh, not exactly.

One of the most significant limitations of this study (aside from its short duration) is that it observed performance at a lower intensity. I’m no expert in cycling, but I do know that cyclists rely on both lower intensity peddling and very high intensity sprinting, typically at the most significant portion of the race. So, aside from the fact that this study was severely limited in its scope of intensity, the results even showed a diminishing effect in some of the participants at a low intensity. As Anthony Colpo points out here, two cyclists saw large declines in their times to exhaustion, and two others saw a moderate increase. In addition, one cyclist experienced a massive increase in time to exhaustion (84 minutes). To say that one individual skewed the overall results would be a massive understatement. The performance of the cyclists was far from “not compromised”.

Considering the above, there were obviously conflicting results and severe limitations to this particular study, so I’m not exactly sure why it is cited so often in favor of low carbohydrate performance. Interestingly enough, Phinney himself came out with a paper titled Ketogenic diets and physical performance in 2004, 21 years after the paper discussed above. In this review, Phinney concluded that, “Therapeutic use of ketogenic diets should not require constraint of most forms of physical labor or recreational activity, with the one caveat that anaerobic (ie, weight lifting or sprint) performance is limited by the low muscle glycogen levels induced by a ketogenic diet, and this would strongly discourage its use under most conditions of competitive athletics” (2). Quite the caveat there, doncha’ think?

It is safe to say that most sports, even those that rely heavily on aerobic capacity, have an anaerobic, high-intensity component that can determine a nail-biting victory or a morale-crushing loss. Based upon Phinney’s conclusion in his review paper: if you expect to perform well at a high intensity, you damn well better be filling your glycogen stores. Ketogenic diets don’t cut it in terms of anaerobic, glycolytic performance.

Because this post is already getting a tad lengthy, I suggest that you read these three posts by Anthony Colpo (here, here, and here) as well as Alan Aragon’s summary of his debate regarding the role of carbohydrates in performance with Dr. Jeff Volek here. All of these posts go into impressive depth, investigating why carbohydrates are of great importance for those who want to perform at a high level.

What Successful Sprinters Eat

Enough with the failure of low carbohydrate diets to produce marked improvements in performance at various intensities. Let’s take a look at what a population of elite distance runners eat in preparation for their record-setting feats.

A study observing the diets of elite Ethiopian distance runners (who hold a large majority of all-time world records) show that they consume a diet very high in carbohydrates, even up into the 600 range (3). A paper observing Kenyan distance runners showed similar results; a diet comprised of up to 75% carbohydrate (4). Furthermore, adolescent male Kalenjin distance runners were found to consume around 71% of their energy intake from carbohydrate (5).

Who to Trust?

So, do you go with the largely speculative, grey area of low carbohydrate performance that has been shown to be detrimental in many cases, or do you go with the glycogen-filling, ATP producing, carbohydrate based diets consumed by elite athletes who do not have time to experiment with becoming “fat adapted”?

The bottom line is that fatty acids simply do not get the job done at higher levels of intensity. Sure, distance running is largely based upon aerobic capacity, but whether or not you’re able to sprint to the finish could be the difference between first place and sucking wind while hundreds of others mercilessly pass you up.

Let me make this clear: I’m not saying everyone should consume a carbohydrate-based diet, and I’m not saying that there aren’t n=1 situations in which low carbohydrate diets have led to improvements in performance. However, based upon the diets of elite athletes who rely on their performance to put food on the table and the current body of research, carbohydrates seem to be extremely important if the desire is to perform at the highest level possible.

The False Dilemma: High Carb vs. Low Carb

This is not so much a myth about carbohydrates in isolation, but rather a myth about the carbohydrate content in the context of the overall diet.

A great benefit of adopting a low carb diet is the tendency to cut out a large majority of the refined carbohydrates and fats that were making up a huge chunk of caloric intake. These foods are typically replaced with vegetables and whole food fat sources, which can be very satiating and often cause a spontaneous reduction in caloric intake.

As I alluded to in Part 1 of this series, cutting out carbohydrates is not the underlying cause of weight loss. Eventually, weight loss comes down to creating and sustaining a caloric deficit. If carbohydrates are a huge chunk of your caloric intake and you completely remove them from your diet, you’re likely to lose weight due to eating less overall. This is a solid perk of low carbohydrate diets, and one that should not be overlooked.

However, I often come across individuals who believe they have to go one way or the other. Not losing weight on a high carb diet? Try a low carb diet. And vice versa. To further murk up the issue, those on low carb diets assume that everyone who is not constantly proclaiming their low carb ideals are on a high carb diet riddled with refined sugars and other “junk” food. The fact is: one can easily consume a whole food, “healthy”, nutrient dense, high carb diet. Those who are entrenched into the militant low carb philosophy don’t want to admit it, but there are people who do just that.

Namely, you can observe the diet of the Kitavans, who live on an extremely high carb, low fat diet and enjoy a very low incidence of obesity and other modern diseases that plague society today. So the issue shouldn’t be narrowed down to a low carb, whole food diet vs. a high carb, highly processed food based diet.

This false dilemma of low carb vs. high carb junk espoused by anti-carbohydrate activists is not only flawed from a logical perspective, but as I discussed in Part 1 of this series, it’s not scientifically sound either. The overwhelming body of research consistently shows that there are a myriad of different approaches that have proven to be effective for weight loss, and excluding an entire macronutrient group is largely unnecessary, even for those with type 2 diabetes and insulin resistance (6).

The point is that there is no one-size-fits-all, as I often state and will continue to state ad nauseum. The wide variety of diet compositions laid out in the research (6, 7, 8, 9) should be enough to convince those with dietary tunnel-vision that their philosophy may not be best for everyone. Creating a false dilemma between high carb and low carb is damaging, and it inherently excludes the middle ground, which seems to be the area where most are successful with their dietary endeavors.

It doesn’t have to be one way or the other. Whole food carbohydrates are very nutritious and tasty, and they can certainly be a part of a balanced diet. The assumption that those who eat a ton of carbohydrates are pounding down potato chips and cupcakes is certainly unsubstantiated.

Wrap Up

I hope y’all enjoyed this series, as I certainly enjoyed writing it! If you have any questions about the series or anything else, feel free to drop a comment below. Also, if you have any comments/feedback/criticisms, I would love to see them in the comment section as well. And if you enjoyed this post and the others in the series, feel free to share them via the floating bar on the left hand side.

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  1. says

    Thank you, thank you, THANK YOU! If I read one more thing on how whole-grain carbs are going to kill me, I am going to go CRAZY! I am a runner so I read A LOT about what the pro’s eat and I found majority of them ate carbs *GASP* Good carbs are an amazing part of a balanced diet. Key word being BALANCED. It doesn’t have to be perfect but I do believe the low carb fanatics think the rest of us eat bread all day. They couldn’t be more wrong. People need to stop freaking out over carbs. I can’t wait until this fad is over and we can all look back (like we do now with the low fat/reduced fat craze) and just laugh. Thank you for the 3 posts on carbs!

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