You might remember V and I started experimenting with a low-carb, high-fat diet last year. We did two cycles of this diet and even ran the Spartan Beast race in ketosis.

This year, we’re taking it to the next level as we attempt to truly become fat-adapted athletes. So I thought we’d give you an update on how this is going.

I got V to tell me about his experience with running on fat (in ketosis) last night while he was doing the 10-minute squat from MobilityWOD.  (The 10-min squat is an essential part of our recovery routines and I included a link to it in my guide to running effortlessly.)

Should you have any additional questions about running on a ketogenic diet, feel free to get in touch via the ‘Contact us’ form on this site or via Facebook / Instagram. I’d also recommend listening to V’s podcast interview with a lifestyle coach who helps his obese and/or diabetic clients return to full health with a high-fat diet.


What did you train today?

I did an easy recovery run, because I had hill sprints yesterday. So I kinda needed to recover and flush all that lactic acid out. I did 4.4 miles at a really easy pace of 10 to 11-minute miles.

I also trained pull-ups and grip strength; so a shitload of pullups, maybe a hundred? I didn’t count, I do it until failure.

Although I did two separate training sessions, I don’t really count the second one. Running is my primary training target right now and everything else is just an addition to that.


How has your running changed since you’ve been on a ketogenic diet? Wait – how long have you been on keto now?

Now, for this specific cycle, it’s been just over 9 weeks. My running…at first your heart rate elevates a lot so you have to adjust to that new pace. You have to slow down a lot and run slower for weeks at first. Now I feel my HR has stabilised, and in another couple of months I’ll reach the levels of potential  I had before going on keto. Except I’ll run even better than on a normal diet, because rather than consuming sugar and burning glucose, I’ll be running on my own body fat. Meaning that, if I have a race for example, I don’t need to consume any gels, supplements or food; I can run on my own body fat for hours.


By being able to “run better”, do you mean running more mileage at lower heart rate? 

It’s everything: running faster, running more sustainably because you don’t need to refuel, running for extended amounts of time. Your body fat is a huge store of energy. People think that you’re starved on a low-carb, high-fat diet like keto. That you’ll have no energy to perform or to feed your brain even.

That’s not true because a) you’d never go into running completely glycogen depleted – your body just makes up the required glycogen from extra protein through gluconeogenesis; and b) on a keto diet, you produce ketones which are actually the preferred source of energy for your brain.

You end up performing better mentally and physically because your body uses fatty acids to create energy, taking them out of your fat cells which are like wallets for fatty acids. You have a huge supply of these fatty acids even if your BMI is relatively low. The body doesn’t have to worry that this supply of energy will run out, so you can put out a sustained, more even physical effort.


Are you saying carb loading is a myth?

It’s not a myth, but it’s nonsensical. You don’t have to do it.

Carb loading is an outdated strategy of race prepping for people who usually consume a lot of sugar. For example, if you’re running a marathon and you consumed energy gels and stuff like that while training, it’s natural that you will need to carb load during the race. You can only store about, what, 500g of glycogen at any one time and you’ll burn through that in a couple of hours of running, if you’re lucky.

Let’s say you’re fat-adapted – you’re running on fat and you won’t have to carb load or refuel. Once glycogen is depleted, if you deplete it, you’ll burn those fatty acids for energy instead, and ketones. This is more efficient and you don’t have to carb load, as long as you’re fat adapted. That last bit is really important.


People have different ways of doing the keto or high-fat diet. What does your regime look like? 

My daily diet is based on a lot of dietary fat, maybe 60-70% of my calories are from dietary fat. Sometimes I fast up until lunch because I’m not hungry. Sometimes I’ll have just a fatty coffee: full of MCTs and some grass-fed butter, blended together with coffee and cinnamon. That keeps me going until lunchtime. At lunch, I’ll feast on salmon, lots of spinach, goat’s cheese, olives, … low-carb stuff like that which is high in fat and so keeps me sated.

Before I run or workout, I usually take some BCAAs with electrolytes to stay hydrated and to prevent muscle damage. On a high-fat diet, you’re essentially starting the workout on an empty tank. You need some essential amino acids to prevent muscle damage, i.e. to prevent the body breaking down protein from muscle into glycogen.


Do you re-feed carbs?

I do a re-feed once a week because I run 5-6 times each week. About 20% of my running sessions are hardcore, so they are glycogen depleting. Just to recover that glycogen I eat 50-100g carb in one evening meal once a week. I wake up in the keto state again as the body has restored that glycogen and I’m good to go for another week.


And what kind of carb do you go for on re-feed days? Pizza?

No, I take berries usually. I find frozen berries are a nice treat after a run. I’ll also eat a Quest bar (not affiliated). They’re really low carb, taste good and feel good. A Quest bar is my carb intake after almost every workout, it’s about 5g net carbs. Sometimes I might have a baked sweet potato or sweet potato fries for my re-feed. (Note from Helena: heaven is baked sweet potato with a slab of butter melted on top and mixed in with cinnamon.Recommended if you haven’t tried it yet.)


You mentioned you did pullups today. So you don’t just run, you also do strength training?

Yeah, I wouldn’t say strength training because too many people focus their training on just that. This is something that Tanner Farenik, a pro OCR athlete we interviewed, pointed out.

So that training addition that I do is partially strength training but it’s just a fraction of my overall training. With training for strength, I tend to follow crossfit endurance principles. I don’t follow specific workouts, but I aim for elevated heart rate and higher intensity. I do the typical stuff: I split my workouts into push, pull, strength training for lower body (legs and core), and shoulders.


So someone who is used to doing strength training a lot or is building mass, should they be worried about losing muscle on a ketogenic diet? Given that 60-80% of what you eat is fat and you’re eating moderate to relatively low protein…

No they shouldn’t because your calorie intake is still really high so you never go catabolic. And plus you consume a lot of meat, a lot of fish which is high in protein.

The reality of strength training is that lots of people go bodybuilding with some running thrown in, that’s the reality. They think carbohydrates will make you gain weight, maintain muscle mass, recover faster. And it is true but there is another side to that coin…

On a keto diet you get the same or even better effects where your liver can just break down the proteins and make glycogen out of it through gluconeogensis. So it’s the same exact effect minus the insulin spikes which make you store fat and the inflammation which is caused by the same effect of excessive sugar. You also recover faster as long as you consume good fats rather than you know fry-ups and trans fats which results from excessive heat, overcooking or charring foods.


To wrap up, when’s your next race?

About a couple of moths away. It’s gonna be the Peterborough Spartan Sprint and then a Super the next day. So two back-to-back races.

And are you gonna fuel up for that race?

Yes, I’m thinking the night before the race I’ll replenish my glycogen so I don’t race on an empty tank (still not carb loading). The morning of the race, I might have half a cup of white rice, with MCT oil and some bacon mixed in. Something I can digest easily so my focus is solely on my race performance.

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