Is a low carb diet for runners killing you?

There's a lot of diet advice out there; some good some bad, some researched, some not so researched, some from people with qualifications, and some from quacks.

There's a lot of diet advice out there; some good some bad, some researched, some not so researched, some from people with qualifications, and some from quacks. Well, I'm Jesse Funk and on today's episode of Runner's High, we're going to explore some of the evidence out there and trying to figure out is a low carb diet runners killing you.

A low carb diet is not a new trend by any means. One article from Harvard actually suggest that we've been doing this for at least 100 years now. It's gone by different names. Dr. Atkins popularized his version of it, so his is Atkins diet and most recently keto. But for a long time, runners had been relatively immune from the thought about low carb diets.

Low carbs, it was kind of the antithesis of what we wanted. Carbs our friends. We're actually even on the other side of the pendulum where we were encouraged to carbo load before race. But that doesn't always stay the same as we look at new diets, we try to figure out what's best for us, what's going to fuel us the best. And sometimes, how do we lose weight and become more efficient in that sense?

I'll be up front with my partisanship right here. I'm not really a big fan of new fad diets. And that's because often, they're untested. They don't necessarily have the background that we need to determine is this good for you or is this not? We have this kind of mentality in this country, a silver bullet solution for whatever our problem is.

If you listen to my episode of the Smart Athlete Podcast with endurance athlete and renowned author Matt Fitzgerald, we talked about his book, Diet Cults a little bit, where we discussed his suggestion of what he calls agnostic healthy eating.

And that is the idea that we should eat pretty much good foods, Whole Foods, you know things that are minimally processed, and not worry about the rest of it. Now I'm paraphrasing Matt, I'm sure I didn't do entire justice to his whole book.

So, if you want to get his full philosophy, check out Diet Cults, you can pick it up on Amazon. You may be able to pick it up at Barnes and Noble, I don't know. But to not miss out on other interviews like that with experts that I talked to like Matt, be sure to subscribe to the channel, hit that button, stay tuned to this channel here.

There are definitely very vocal advocates for low carb diets for runners. One of those advocates is Tim Noakes, Dr. Tim Noakes. You may have heard about him. If you've done any research about low carb diet, specifically for endurance athletes or runners, you've probably come across Tim Noakes.

He has a pretty compelling story and a lot of kind of persecution that's gone on in his personal life, through the government, where he lives and then getting out of jail. It's quite a story to listen to, so if you haven't listened to that it's pretty interesting if you're interested in people.

But I can tell you that at least one of my guests here on the Smart Athlete Podcast has call out Dr. Noakes for doing poor science. And that's kind of the trick, though, isn't it? We as laymen, don't always dig into the science. And that's part of what I see my job as, as bringing information to you. I’m trying to dig into the science and see what is going to actually work for you.

So, we have to be careful about what we look at, who we listened to, and remember that we are prone to being inside of an echo chamber. We want to listen to the people that already agree with our point of view, instead of being entirely critical about what's going on.

One disclaimer right here, I am not a registered dietitian, I am not any kind of registered, food nutritionist, anything like that. I'm doing my best to look through the science. Look through the opinions of experts and bring those to you.

So, remember that as we continue forward with this conversation, I'm doing my best to bring you different opinions and different research. But I myself am not a registered dietitian. I do employ a registered dietitian to bring you approved recipes for endurance athletes, you can find that on We have a new recipe every single week.

So, back to our low carb diet. Right now, in the mainstream culture, it's often referred to as the keto diet. And this is, as I understand it, so don't quote me on this, I'm doing my best to really get my head around all of it. So, as I understand it, we're looking to induce a state of ketosis when we are having this low carb diet.

The idea being normally, our body uses sugar in our blood as a source of fuel and then glycogen in our muscles as well. So, when we don't have enough carbs to produce these things, our body in turn takes fat turns it into what are called ketones, which is where ketosis comes from, and uses those ketones for fuel.

Now, the idea of this is, in theory pretty nice for runners. The whole idea of running and a lot of the things we do as runners for training is to make our bodies burn fat more efficiently. So, we kind of think about these two ideas where if we get into a state of ketosis, then our body is forced to use fat as fuel.

And when we're training, we're trying to make fat a more efficient fuel at the same time. So, if we could put them together, can we become a better runner or a faster runner? That's the whole idea about a fat adapted runner or a low carb diet for runners.

There are definitely some naysayers in the running community for low carb diet or keto diet. And one study that recently looked at this particular diet, looked at 42 runners, and they're roughly the age of 37. It looked at them on a keto diet over a six week period. They tested them on a couple of measures, including VO2 Max and LDL cholesterol.

After following a keto diet, and I'll have this down in the description below so you can check out the study yourself. After the keto diet for six weeks, their VO2 Max drops 2.4% in their LDL cholesterol went up 10%, and that's the bad cholesterol. So, really not great results from that particular study.

Unless you think I'm here just to poo-poo on low carb diets are actually is another study I found and this looked at highly trained male athletes. It ended up with eight of them and what happened on under similar conditions, they put them on a keto diet for a period of time, and then they tested them before and after.

They tested a few different measures and those were intensity of exercise. What they found was that performance at low to moderate intensity exercise actually increased post keto diet, which is really you know, that makes sense. Just like the theory I said earlier where we want to be able to burn fat more efficiently. And at lower intensities, we do burn fat more efficiently.

These people also had their BMI and body fat go down. Keep in mind, these are highly trained male runners, so people that have been training for more than five years. The big kicker, and this is the important thing, these this is the thing that continues to seem to show up and the things that I find is it at high intensity, their performance went down.

Think 5K pace or faster, which again, we're just going to think about it try to be a little bit intuitive. The higher you go and intensity, the harder you're going, the more glycogen you have to use. So, if you don't have that available to you, you don't have that process available to you, then you're probably not going to perform as high a level.

There are potential hazards to a low carb diet or keto diet for people with certain medical conditions like Diabetes. Now, as I do often on videos like this, I recommend for you personally, go to your doctor and get their recommendation. I nor anybody else here on YouTube giving you information has the ability to diagnose or prescribe for you. We are not medical professionals. We're just trying to curate information the best we can and bring it to you. So, when in doubt, seek somebody who's licensed and qualified to give you medical advice.

I think I can say pretty definitively that a low carb diet is probably not going to kill you. It does serve as a nice clickbaity type headline. So, thanks for clicking on that and staying with me. But overall, I think the jury is out in terms of is a keto diet positive or negative totally for runners. One thing I would be interested in seeing and remember this is complete conjecture on my part is whether over time, we see that a keto diet isn't necessarily best in the long run.

I kind of think about again, this is the conjecture part is keto possibly, okay, and remember, this is a naturally occurring phase that happens within our bodies. We're not doing anything abnormal, this is something that happens naturally.

Is it something that we adapted over time, our bodies adapted over time to deal with a lack of carbs for a short period of time? That's something I'm interested in. There's no studies that have been done on that. It's just something that's a curiosity of mine.

So, I'm wondering you as a runner, what have you experienced? Have you done a low carb diet as a runner? What anecdotal evidence or scholarly research can you share with me? Leave them down in the comments below, I'd love to hear from you. I'll see you next time on the next episode of Runner’s High.

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