LCHF and fat adaptation in triathlon with Jesse Kropelnicki and Steph Lowe | EP#147
Jesse Kropelnicki and Steph Lowe discuss LCHF for triathletes and endurance athletes. This interview highlights that there's not just one way to skin a cat with LCHF. Different triathletes will fall on different points on the spectrum of LCHF. The approaches of Jesse and Steph differ mostly in that Jesse prescribes a train-high, race-high approach, whereas Steph prescribes training low and racing moderately high.
Discuss this episode!
- Let's discuss this episode and the topic in general. Post any comments or questions in the comments at the bottom of the shownotes. Join the discussion here!
In this Episode you'll learn about:
- Steph's approach to LCHF (low-carb, high-fat diets): real food, avoid extremes, and train low, race high.
- Jesse's nutrition approach: "unprescribed LCHF" (less focused on macronutrients) in day-to-day nutrition, with train high (and train the gut), race high.
- Potential benefits of LCHF for endurance athletes.
- LCHF versus "clean eating" and non-LCHF with unprocessed foods.
- Myths and misunderstandings around LCH.
- How the race-course is the world's best lab for testing nutrition strategies and verifying that they work.
Sponsored by:
Precision Hydration
One size doesn't fit all when it comes to hydration. Take PH's free Triathlon Sweat Test to get personalised hydration advice tailored to what you're training for. Use the promo code THATTRIATHLONSHOW to get your first box or tube of electrolyte product for free!
ROKA
The finest triathlon wetsuits, apparel, equipment, and eyewear on the planet. Trusted by Lucy Charles, Javier Gómez-Noya, Flora Duffy, Mario Mola, and others. Visit roka.com/tts for 20% off your order.
Shownotes
Where to find Steph Lowe
4:24 -
- My online home is thenaturalnutritionist.com.au and I'm based in Melbourne, Victoria.
- I work with lots of endurance athletes but mostly triathletes.
- I work with people who want to adopt a real food and LCHF approach to their performance, recovery and longevity.
Where to find Jesse Kropelnicki
4:47 -
- We've got several websites where listeners can reach out to us:
Jesse's previous appearance
What is LCHF?
5:20 -
- LCHF stands for lower carbohydrate, higher fat diet.
- There's lots of different versions of that, but the over-arching aim is taking nutrition back to basics and focusing on food in it's whole food form.
- Food that comes out of the ground, off a tree or from an animal.
- My [Steph's] model of LCHF is definitely not keto.
- When we look at the literature we know what classifies as a low carb diet is 25-150g carbohydrate per day.
- A really conventional percentage breakdown is 15% carb, 20% protein and 65% fat.
When we discuss percentages it's relative to the overall calorie intake. - We need to look at grams as well because everyone has their individual carbohydrate tolerance.
We know that 150g per day will suit someone with good carb tolerance, usually very active and already at their goal weight. - The spectrum goes all the way to the other end: carb intolerance is type 2 diabetes and to reverse that the dietary prescription is as low as 25g of carbs per day.
- Athletes generally sit somewhere in the middle, especially if they're still looking to get a little leaner.
- In general we would do blood tests and look at factors such as overall activity both in training and day-to-day.
We'd be looking for where that individual sits on that carbohydrate spectrum. We can then adjust the ratios accordingly for the proteins and fats.
Jesse's nutritional approach for endurance athletes
8:15 -
- The approach we take is very whole food based, and we focus on trying to keep blood sugar stable in periods between workouts.
- We try and keep manufactured foods and high glycaemic index food that have a lower nutrition density particularly positioned around workout sessions where they will provide a positive impact to that training session.
- Back in the days when I was doing bodybuilding and was quantitative with my nutrition, I was very focused on the distribution of macronutrients.
- Later when I started working with endurance athletes, I realised the stress it takes to do that type of tracking isn't worth it, given all the other things in an athletes menu of things to do.
- We try to take a qualitative approach to nutrition with certain types of protocols and logic with how we eating during the day. It takes care of those macronutrients on their own.
- This typically ends where the athlete who isn't training at all (recovery week) is taking 40% carbs, 30% fat, 30% protein.
- Whereas the athlete that is training 25-30 hours a week may be taking 60-65% carbs, 15% protein and the remainder fat.
- It depends on the training volume and ideally the macronutrients suggests themselves.
- This shouldn't add additionally stress to their life or programme. We'd rather they spent this time on sleep, massage, etc.
Intake of carbs and fats for endurance athletes
10:25 -
- Jesse: Endurance athletes typically end up being too high on the carbohydrate front and too low on the nutrient density front.
- I.e. eating carbs that tend to be void of nutrient density.
- These are usually not whole food options, namely lean meats, fruits and vegetables, nuts, seeds, legumes. These are nutrient dense carbs and tend to keep blood sugar stable, and provide immune protection.
- Steph: prior to working with me they're usually following some version of low fat and relying more on carbs.
- There have been huge campaigns for people to be afraid of fat as a macronutrient (e.g. told it'll make us fat, give high cholesterol etc). These have been disproven but there's still a lot of fear, especially with saturated fat.
- Anyone that has followed a conventional dietetics model or is working in sports nutrition, they're following a really high carb approach.
- Most people are over-eating protein as well - 20% protein is a big drop for most people.
- Most people are aware of the benefits of real food - we can't question that nature knows best.
- Working out what is best for each individual is important because genetics, current lifestyle and activity levels, and existing carb intolerance all play a role.
- Carb intolerance often comes from following a conventional food pyramid or sports nutrition guidelines.
Benefits of LCHF for endurance athletes
13:55 -
Steph
- When we look at an LCHF model, the real focus is on lowering intake of refined carbohydrates. These have formed the bulk of the food pyramid and dietary guidelines in the west. E.g. breads, cereals, pasta, musli bars, low-fat yoghurt.
- These foods are not in their natural whole food state, usually they're created in a lab.
- Refined carbs eventually become sugar, and sugar has been proved to be highly inflammatory. We're trying to avoid inflammation!
- We're trying to reduce foods that produce a lot of the reactive oxygen species, which require a lot of work for the body to mop up.
- From a pure recovery sense, the role of the body is to produce an anti-inflammatory environment. We can support this by eating whole foods.
- Inflammation is also associated with many lifestyle diseases (e.g. obesity, metabolic syndrome, type 2 diabetes. It's essentially our enemy for overall longevity.
- When we're moving into an LCHF template we're adding foods that are anti-inflammatory in nature.
- When we increase our intake of polyunsaturated Omega 3's, their whole role is to create this anti-inflammatory environment. This is really important to recovery, ongoing performance and athletic longevity.
- The inclusion of foods like saturated fat, which have been demonised for the last 5 decades, is so important for many reasons:
- We often see when we can expand our intake of healthy dietary fats we're able to keep our insulin low.
- Insulin is the fat storage hormone that is produced in the presence of excess carbohydrate.
- When we remove the excess carbs, we're allowing our body to have a low level of insulin, which allows us to promote a fat burning environment.
- We want to be able to access fat for fuel because it's an unlimited tank.
- Provided you're eating the right balance of macronutrients you can still use your muscle glycogen, you still have the fuel available for any glycolytic or high-intensity exercise. It's therefore a duel-fuel system.
- If you're eating a high carb diet you'll blunt that fat-burning capacity and won't have access to that tank. You'll only have muscle glycogen and any exogenous carbohydrates that you consume.
- This is a very limited energy supply which is why you see a lot of long course athletes hitting the wall.
Jesse
- Typically for the sprint and olympic distance athlete, fuelling won't be the primary limiter on race day. You can therefore get more radical with your approach.
- I agree with everything Steph said, becoming more fat efficient is something we need to be doing just as human beings throughout the day.
- Things become more complex when you step up to ultra long distance racing - namely Ironman.
- Athletes here are training 25 hours a week. Taking an approach with lower than 200g of carbs per day would be very difficult.
- If you were to become fat adapted to the point you could train on a very low quantity of carbs and focus more on fat, although you've made it so you demand less on race day the problem is the rate at which you de-train the gut to handle a small amount of fuel happens quickly.
- We are training the athlete to handle more carbs, sodium and fluid in training sessions and on race day they have a higher level of insurance.
- The amount that you train the gut to handle more opens up the window of insurance that they'll be able to handle what they require.
- The downside if you're consuming more carbs is that you don't have nutrient density.
- This makes it more important that any time you're not training or racing you need to be extra focused on nutrient rich foods to get the benefits Steph described.
- You can be on an LCHF diet for all periods between training sessions - which we advocate.
- The objective isn't as much focused on nutrient density in training, it's about making sure you address the primary limiter in Ironman. You need to practice ingesting this stuff to the level you require.
- There's a LCHF diet for periods between sessions and then there's what you're doing in the session itself.
- The summation of those two gives you the end of the day macronutrient count.
- We advocate you take an LCHF approach to your day-to-day eating, but during the sessions themselves we're injecting more carbs. These are bland, low nutrient dense carbs which are high in glycaemic load.
- For the short course athlete, when it comes to the training sessions you could get more risky in reducing the carbs they have in training sessions.
The fuelling on race day won't be as much of a limiter so you don't need to practice it to train the gut as significantly. You can take a more holistic LCHF approach. - I've worked with a lot of professional short course athletes who are training high volumes. We'll take a more fat adapted approach during the training sessions even though their volume is high.
- It's not just about the training volume, it's about meeting the race day demands and being specific to these needs.
Fuelling in training
24:18 -
Steph
- We do things differently in the majority of training compared to race day.
- I agree that you need carbs on race day, and our model is: train low, race high.
- I think the limiting factor for Ironman is your ability to access fat for fuel.
- For most people, we're trying to keep the load at moderate intensity, which is the best place to burn fat for fuel. A lot of people are unable to do this.
- This 90g of carbs per hour, or recommendations like 1g carbs/1kg body weight - the vast majority of people can't tolerate this.
- No matter how much you practice there will still be the impact of fructose in the higher intake.
- We know you only have the ability to consume up to 60g carbs of glucose or maltodextrin, beyond that you need to look at multiple carb transporters.
- All products are marketed giving you the 2:1 glucose:fructose ratio as it's the only way to get the high intake.
- Fructose is sugar that causes a lot of water to be drawn into the gut.
- This gives the typical gastrointestinal issues, and why we see too many athletes in the bushes or vomiting their fuel plan up on the side of the run course.
- In training we're trying to fuel minimally. It's not zero and it's not keto, it depends where that athlete starts from.
- If they've been practicing 90g carbs/hour we're not going to drop them down to 25g/hour immediately. We're going to work backwards and train their body to start to rely less on the exogenous carbs and more on external fuel supply.
- If it's an athlete starting from scratch, it will depend on body weight but we'll likely be looking at around 40g carbs/hour. When we're consuming that range we know we can do it from purely glucose.
We then don't have the GI issues associated with fructose. We can also choose more natural versions of glucose so we aren't consuming inflammatory fuels. - Race day is naturally high intensity, and fuelling requirements are always dependent on intensity. What you need in a long, slow distance session will look very different to any session that is race day replication, or race day itself.
- We would pull out a couple of key training sessions that replicates race day, and test whether they need slightly more carbs based on their heart rate.
- There will be practical and logistical considerations. E.g. It's really hard to carry 90g carbs/hour for an Ironman that's over 8-17 hours. For a lot of people they don't want to have to go anywhere near that volume.
- It's more than training, but we want to be able to rely on fat for fuel and less on exogenous carbs on race day.
LCHF alongside 'real food'
28:52 -
Steph
- If you're eating 150g carbs per day, you can definitely fit fruit and potatoes in that.
- White potatoes have been demonised due to their high GI. GI stands for glycaemic index and it's a measure of how quickly the food increases your blood sugar.
- As soon as you add fats to a white potato, or combine it with a meal where you're consuming protein, the GI lowers considerably.
- Certain whole foods carbohydrates definitely have their place.
- We need to be mindful of looking after our long term gut health with LCHF.
- This starts with diversity of the plate. Also avoiding refined sugar, Omega-6 oils and trans-fats.
- But we need to be providing the right fuel for our beneficial gut bugs. We know how important resistance starch is to feed the beneficial gut bugs in the large intestine.
Sweet potato, potato and white rice, become resistance starch when cooked and cooled. It can be re-heated but the process of being cooled is what turns it into resistance starch. - One of my problems with a typical keto diet is starving gut bugs. This creates a whole host of problems for day to day immunity, neurotransmitters and nutrient absorption. In the future it creates more systemic issues because we know all health starts with the gut.
- Basically potatoes have their place, but they're foods you need around training to act as a muscle glycogen.
- For most people, after a high intense session is the best time to consume more starchy food.
Listener questions
31:36 -
Miko, Finland: What is the affect of LCHF diets on an athletes immune system?
- Jesse: The approach we take with the Core Diet and what Steph has described is similar in between training sessions, because these are foods we've evolved to eat.
- These are nutrient dense food items that keep blood sugar stable and improve immunity.
- Where things become different is around fuelling.
- In an ideal world I'd suggest athletes ate lean meats, fruits, vegetables, nuts, seeds, legume and dairy during training and racing sessions.
- However we all know this would not lead to high level performance because of the extraordinary feats these athletes do, especially extreme endurance athletes.
- Unfortunately we need to have grains and refined sugars, specifically so we don't have nutrition as a limiter on race day.
- The overall impact these carbs have on an athletes life over a year or more is difficult to describe.
- I've worked with athletes who are at the top of the world, and my stance is if you are focused on nutrient dense foods at all times between training sessions, you get a bit of a pass.
- You get to provide your body what it really needs to perform in training and racing.
How important is carb minimisation
33.46 -
- Mikael: I have a very high focus on nutrient density, but I also eat a lot of carbs. Most of my carbs are sweet potatoes, potatoes and fruit/veg - I very rarely eat pasta or rice.
- I fuel in training with sports nutrition.
- I know if I calculated my macros the percentages would be around 55% carbs on an average training day.
- How important is the minimisation of carbs?
Steph
- I think it needs to be very individual which is why LCHF needs to be a spectrum and not a defined number of grams per day.
- You may have a fairly good carb tolerance - we would need to look at your blood glucose levels, your HPA1C, your fasting insulin, and inflammatory markers (e.g. high triglycerides, or high cholesterol to HPA ratio).
- We would need to look at these to see whether your diet you're using now will serve you into the future.
- I agree that a short term consumption of refined carbs, when talking about athletes who tolerate them well, won't be noticeable straight away.
- We're talking about athletic longevity - we want athletes who don't have to retire because of inflammatory associated injuries that could have been stopped through diet changes.
- At the end of the day, carbs still get converted to sugar so you have to think about what impact that has on your physiology in the long term. Even whole food carbs such as potatoes, fruits and vegetables will still get converted to sugar.
- Clearly real food is the answer to longevity, but you may or may not need to shift macronutrient levels based on physiology now, and tracking that into the future.
- HPA1C stands for glycolytic haemoglobin and it's a 3-month trend. Rather than just looking at blood glucose levels which will basically just tell you what you ate last night, HPA1C looks at the 3-month trend.
It's a measure of what sugar is stuck to your red blood cells. The higher the HPA1C, the more you're moving towards pre-diabetes. - We look for an HPA1C of 5.3%. Any athlete that sits over this is clearly eating too much carbohydrate and we might try to reduce it. We would reduce it and increase fats accordingly until we got HPA1C back under 5.3%.
- Once you've addressed that you can experiment going up again. There's an underlying genetic component which can be looked at from a family history standpoint to start.
- I believe this is one of the most important blood tests there is.
Drawbacks of an LCHF diet for endurance performance
38:18 -
Jesse
- The biggest risk about employing LCHF across training and racing is de-training the gut to be able to handle any amount of carbs, fluid or sodium.
- Although the athlete may be more fat adapted and reduced the amount they require on race day, they've also reduced their ability to handle carbs, fluid and sodium.
- Even though their need has reduced, their tolerance has reduced at a faster rate.
- They may then toe the start line unable to tolerate the reduced amount that they've worked hard to create.
- With our business we do somewhere between 200-300 fuelling plans per year, we've been doing it for 15 years. The primary thing we see is athletes not practicing their fuelling enough.
- They try to take a more fat adapted approach and come race day they can't even handle the small amount.
- It doesn't mean we're against fat adaptation and keeping blood sugar stable.
- We try and do this for a vast proportion of the person's life outside of workout sessions.
- The workout sessions themselves are about training the gut to be able to handle what the body requires.
- This is particularly important for long course racing.
- For short course racing we can get more fat adapted with training because it's less likely that fuelling will be the limiter there.
LCHF at high intensity
40:29
Jesse
- It depends how radical you get - there's some advantages to doing training in a low carb state to get more fat adapted, but still supplying some carbs on race day.
- You still need something even for the higher intensity sessions and races.
- For the ITU athletes we work with we take a lower carbohydrate approach to the fuelling and take a more fat adapted approach.
- On race day we end up somewhere in between with the total carb quantities.
- Contrast that with what we do with pro Ironman athletes or top AG:
- We've had females who weigh 124lbs (60kg) handling over 130g of carbs an hour.
- These are the same athletes that have set some of the faster run times in history at Kona.
- I get to the point where I just don't care what the studies say because I have the real world results! It's amazing what humans can handle if they practice it.
Steph
- It's a common myth that 'LCHF makes me lose my top end' - I think that's a poorly prescribed diet, with the wrong macronutrients in the spectrum.
- When it comes to high intensity we know you're using muscle glycogen.
- After that session you want to replenish the muscle glycogen by consuming complex carbohydrates in the meal you consume post training.
- It's also going to come down to maintaining muscle glycogen which is hard to do on a keto diet. It's rare than an athlete I would work with needs to be anywhere near 25g carbs per day.
- We want to be supporting performance, so that's why we want to work out where the athlete sits on the spectrum. We can then make sure we're fuelling with adequate whole food carbs to support their intensity.
- The more intensity you do, the more carbs you'll be able to consume. This will change, day to day, month to month and year to year depending on your goals.
- Long sessions should be done at a lower intensity where we are burning fats, and therefore have a lower requirement for carbs post training.
- Anything short and sharp - e.g. intervals, I'd get the athlete to have anything from 30-45g carbohydrates post training to start. We're looking at 120-150 calories from a whole food carbohydrate.
- It's very individual, though, we'd track things like ongoing satiety, recovery parameters, ongoing performance.
- We can increase this but we also need nutrients from non-starchy vegetables, quality protein and healthy fats.
- The complex carbs like the sweet potato or fruit, is the last to the plate nutrition to make sure we're adding it to the recovery meal.
Myths about LCHF
44:53 -
Steph
- The two main ones are making sure we aren't starving our gut - one of the myths is that people believe it can contribute to disbiosis.
Disbiosis is an imbalance in our internal ecosystem. If we're adding the right vegetables and fuelling our body with resistance starch and looking at diversity and beyond, we can avoid this. - The second is that it will make you slow which we can absolutely avoid by fuelling with the right balance of macronutrients.
Listener question
45:40 -
Dean - What is your point of view on LCHF for older athletes? Are there any special considerations?
Mikael - Are there special considerations for females compared to males?
- Steph: I get my females on a slightly higher macronutrient percentage. Usually 20% carbs, 20% protein, 60% fat.
- This is relative because they are naturally going to be eating less calories. There are definitely females that thrive on 15% carbs but it's usually over time.
- I don't think age has anything to do with it, it's more intensity related.
- If the older athlete is still doing a significant amount of high intensity, they will need more carbohydrate. If they are doing more MAF training or low intensity training they'll need a lower volume of carbohydrate. Your carb requirements are always relative to your intensity.
- Jesse: we're really performance focused when it comes to the fuelling piece of it.
- Instead of looking at what the requirements are from an intensity standpoint, we look at what the requirements are from the gut being able to handle it standpoint.
- If we believe on race day the athlete requires 90g carbs per hour, we train at this level regardless of the training session.
- We understand that the requirements of the sessions are different, but that's not what we're doing with the fuelling at that point.
- We're specifically focused on improving the ability to handle the requirements on race day.
- Even in the final ten days, we'll go higher than the requirements - e.g. 110-130g per hour.
- Then we bring it down on race day and there's no gut issues at all.
- It's not demographic specific, but it explains why we don't adjust things in terms of intensity.
- With females we take a 10-15% reduction in the carb quantity associated with the carb load. That's the only nutrition-related demographic manipulation that we do.
Jesse's athletes going to Kona
48:54 -
- The athletes I presently coach are:
- Jocelyn McCauley
- Lindsey Corbin - who just won IRONMAN Wisconsin.
- Jodie Robertson - who was second at Ironman Texas this year.
- I've done Heather Jackson's fuelling plan
- Rachel McBride
- It's utilising an approach that's somewhat hybrid of everything that's been discussed on the podcast today.
- It's the same approach we've taken for 15 years.
Related listening
LCHF vs HCLF
55:15 -
Relating to a recent study which discussed this diet in race walkers and went viral on social media.
Steph
- To be honest it's pointing out the flaws in any more recent studies around LCHF - you need to have done an adaptation phase.
- If an athlete can't burn fat, then reducing their carb intake is going to reduce their performance.
- These studies need to ensure their athletes go through the 12 week adaptation phase so they can burn fat.
- Any athlete that wants to burn fat for fuel, needs to take the time to train their physiology to do that.
Jesse
- Studies are only studies, they're good to point you in a direction but reality is always the best lab that you have.
- Testing some of the things you read in studies in the real world is where you find out the realities of things.
- I've been around the sport long enough to know that the studies come and go.
- There were studies that I argued with people on in 2002, and years later they come back and say they've done another study and I was actually right. I was just coming from the basis of real world testing.
- There's always flaws in studies, but they make you think so it's still valuable to read them.
Rapid fire questions - Steph
53:12 -
- What is your favourite book, blog or resource related to endurance sports or nutrition?
- I'm a massive fan of Phil Maffetone and his website is really great: philmaffetone.com
- What is your favourite piece of gear or equipment?
- At the moment it's my yoga mat. I'm 15 weeks pregnant so not doing as much running or riding at the moment.
- I believe yoga has a very important place to balance all the endurance work we do as triathletes.
- Who is somebody in endurance sports or nutrition that you look up to and admire?
- Dr Phil Maffetone - he's a pioneer who's been in this space for over 40 years.
- Jeff Volek - who's been researching low carb diets for decades.
- Tim Noakes - I admire him, especially for his ability to stand up and say he's wrong.
Key takeaway
- Eat clean! This is the main message from today's episode.
- I'm not convinced personally that I should go on an LCHF diet, but I do eat very clean.
- My carbs come from vegetables and fruit primarily, and also sweet potatoes and potatoes.
- If you're not eating clean, moving towards an LCHF diet may help you move towards clean eating too.
- The importance of nutrient timing.
- If you're on an LCHF diet when you get your carbs does matter a lot.
- If you're following the Jesse approach you'll be training your gut to absorb carbs.
- With Steph's approach, where you're not consuming that much nutrition during training, the time to get your carbs would be after your workouts to replenish glycogen stores to allow you to perform well in your next workout.
- Going towards at ketogenic diet was not something Steph or Jesse recommended for many reasons.
- Being pro LCHF does not mean you should take it to the extreme.
- Some athletes will be more low carb that others, but the extreme may not be beneficial.
- The real world lab versus studies.
- Personally I still don't think there's scientific evidence to support LCHF from a performance stand point, but I agree with Jesse 100% that the best lab is the race course in the real world.
- If you follow something to a T, but you perform poorly, you need to change things.
- If something works really well time and time again but the science doesn't back it up, keep doing it regardless, of course!
- Performance is the best measure of performance as Andy Coggan once said.
- Don't get held to the scientific studies too tightly.
- Take health into account as well though!
Links, resources and contact
Links and resources mentioned
Connect with Steph Lowe
- The Natural Nutritionist - Steph Lowe's nutrition business
- The Real Food Reel - Steph's Podcast
Connect with Jesse Kropelnicki
- QT2 Systems - Jesse Kropelnicki's coaching business
- The Core Diet - Jesse's nutrition business
- The Endurance Training Diet & Cookbook by Jesse Kropelnicki
Connect with host Mikael Eriksson

Hi! I'm your host Mikael,
I am a full-time triathlon coach and an ambitious age-group triathlete. My goal is podium at the Finnish national championships within the next few years.
I first started the website Scientific Triathlon in autumn 2015 as a passion project to share my learnings with a larger triathlon audience. Later on, in early 2017 I started the podcast That Triathlon Show.
I sincerely want you to contact me to
- Send me feedback
- Give constructive criticism
- Request topics and guests for the podcast
- Send me your triathlon-related questions
- Tell me that you've rated and reviewed That Triathlon Show so I can give you a shout-out on the show and tell you how much it means to me!
MORE ON THAT TRIATHLON SHOW
- Go to the That Triathlon Show main page
- Go to the full Episode Archives
- Check out these popular episodes:
Enter your text here...