I recently did a 6 month Ketogenic diet experiment, to improve fat oxidation capabilities, to enhance the body’s aerobic cardiovascular capacity for long distance training and racing. 

As with all people trying to improve at their chosen sport, curiosity about training and racing led me down this avenue because I seemed to struggle at doing long distance low intensity workouts, often feeling low energy even though the session was easy.

I started researching why this was happening and heard about the train low/race high approach (checkout Team Sky’s nutritionist James Morton’s work on mitochondrial biogenesis) so I started implementing a once a week session that could be incorporated in to your training to improve fat burning capabilities.

This was an easy technique to use and I did it 3/4 times, and was reasonably effective, I found myself improving doing these long distance low intensity sessions (I was obviously more of a sugar/glycogen burner) the session would be done by eating a carb rich meal to get the most from a 1. 5 hr session of VO2max intervals with the objective to burn out glycogen stores, in liver and muscles, post workout fuelling would be fat and protein only to shock the muscles in to a biogenesis mitochondrial upgrade, due to the abstaining of carbohydrate post meal fuelling, this would be followed up by an hrs workout at steady state zone 1/2 the next morning or a second afternoon session, to force even more adaptions, these were a great introduction to fasted sessions, when I first started them they were awfully hard, 25 mins in often couldn’t even run or turn the pedals, I started to improve after a few but always knew there was more to this after reading about keto diet and going in to ketosis to improve fat burning capabilities even further. I started researching how to approach this as much as I could and I thought I'd incorporate it in to a 3 day water fast I had planned, after the Xmas period. The fast was always going to be tough, 3 day fasts are never easy but a great way for the body to clean up cellular structures through autophagy and it also pulls out any toxins out of the adipose and sub cutaneous fat tissues, which you'll be using for energy once on the diet, as long as you’re not ingesting too much exogenous fat from your diet (important to bear in mind if weight loss is your goal) best time I feel to start a ketogenic diet is in the base building phase of training, so you can do low intensity training in the zone 1/2 range, I think doing 1/2 months is a great way to improve metabolic capacity but this will be different for each individual depending how sugar dependant in life and sporting activity they are. 

Nearly all endurance events are almost all done in a steady state, some are more demanding and some are less (depending at the level of athletic ability...e.g. professional) but all are done through the Oxidative Phosphorylation Pathway or some would know this as aerobic, which is mainly through the burning of Fat and Glycogen stores (and protein if event is very long and substrates coming in are low) So to make an athlete more efficient we have to work on getting that system able to be less reliant on using glycogen, and up-regulating fat oxidation, this will improve an athletes ability to go longer for less energy coming in and be less likely to have GI issues during their race. 

If you look at sports nutrition and everyday food intake for most in society, it's high in sugar and refined foods, (most gels are maltodextrin corn derived with bad sweeteners in also) and if your unaware about dietary basics of better eating habits, you’re probably running mostly on burning either the sugar coming in from your diet or your glycogen stores, weather that be in your daily activities or during training or racing, so if you can train the cardiovascular system to be burning adipose tissue around the body, you’re going to become more efficient at steady state exercise (also necessary to train effectively too) and that is where a ketogenic diet intervention comes in to play, doing a phase of easy zone 1/2 training or even just walking to start with, while going through the first phase of ketogenic adaption of 50 grams of carbs or less, giving the body as little stress as it can handle during adaption phase because the first few weeks the body will be massively still craving sugar!!! and this can be quite challenging for some, depending how badly their system was using sugar in diet and utilising glycogen during training rather than fat oxidation during daily life and training. 

What is Ketosis?

Ketosis is the bodies way of protecting itself from dying, the brain is depending on 130grams of glucose to survive daily but while there's not enough carbohydrate coming in to be broken down in to glucose through Glycogenolysisit has an amazing back up system to help survive times of starvation. While in Ketosis the liver starts using ketone bodies to make fat in to a soluble state to pass through the blood brain barrier to fuel this most important organ, the great part about of ketone bodies is the brain and heart seem to thrive on this fuel better then glucose (I found this to be true while in ketosis, often on days when ketones where above 1.5 mmol I'd have far superior cognitive function) 

Best way to transition into Ketosis

To get in to ketosis is relatively easy, especially for an athlete, I done it through starvation but you can simply do 90mins of VO2max intervals to burn the liver and muscle glycogen stores down, on average we hold 400/500 calories in liver and 1400/1800 in muscles, depending on muscle mass of the athlete/person. if you've read about the Ketogenic diet you'll know it’s a strict diet that requires someone to be on less 50/25 grams of carbohydrate a day to stay in ketosis and 65/80% calorie intake is coming from fat, this can be quite daunting for people to understand, because society has swayed most people in to thinking this amount of fat intake is going to kill them, which is completely untrue as long as the fats are eaten on a low carb diet without high carb breads, starches and high sugar refined foods.

Good supplements will help during transition phase

Number one supplement I feel is getting hold of decent electrolyte product or use Celtic sea salt/Himalayan salt and potassium supplement, the reason you need more electrolytes is because when the muscles are depleted of glycogen the body can't hold on to the water coming in, so more sodium is needed and in very high amounts (especially if training, no one wants cramp during the session) sometimes 5g to 10gs depending how active you are, A lot of people suffer with keto flu to start out and there are many reasons for this happening, electrolyte imbalances are up there as number one but this can also be because the adipose tissue that is being used as energy can be full of toxins depending how good you've been with your diet over the years. Other important supplements are MCTs medium chain triglycerides really do help in the transition phase because they can help up the levels of ketones in the body while the body is getting adapted at burning more fat that is coming, as the system gets better at fat oxidation it’ll be coming from adipose tissue, especially while training!!! Buying decent C8 or C8/C10 MCTs which are non-hexane produced is best (keto Pro) food based multi vitamin to cover micronutrients, I use a lot of chlorella and spirulina in capsule and powered form. Magnesium or ZMA to help relax muscles and to get deeper sleep, decent omega 3 supplement like cod liver oil if you’re not eating a lot of oily fish like sardines Mackerel, during first week you can use bhb supplement to increase ketones, KetoPro do a great pre-workout that really does make training at fat burning capacity much easier (especially during adaption phase) Stevia sweetener is good for getting off the sugar it may taste different at first but you get used to it. 

Keto friendly treats, cheats that make staying under 50 grams a day easier

So I’ll start with how I would eat on a typical day, for the first 2/3 weeks it's definitely preferable for you to track macros on MyFitnessPal or some sort of tracking app, this is important to know you’re getting enough fat in, not eating too much carbs, and protein which can be made in to glucose through Gluconeogenesis, which is not that bad later on but at the start it's something that is not ideal (more protein will be needed if you’re an athlete)  I would generally skip breakfast as such and have a black coffee or if I did feel hungry I would make a bulletproof coffee with MCTs, bit of grass-fed butter and a small amount of collagen. This would increase ketone production and make you feel satiated, I dropped the butter once adapted, although it does make coffee taste amazing it’s still a lot of fat calories and to be honest I would rather be burning them off our bodies then consuming in our foods and drinks, that's one of the good things about MCTs they don't store as fat, and can be utilised directly through the portal vein as energy quicker than sugar! Afternoon would generally be salad, with lots of Spinach, Rocket and Lettuce, to help fill the meal out (leafy greens are a great way to stay healthy and feed gut bacteria) Avocado, Eggs, fatty fish like Mackerel, Sardines, herring, tuna with ample oil, like avocado oil, olive oil, macadamia oil, butter or some nut butters too like Macadamia, Hazelnut, Almond, pecan, Brazil nuts are all low carb and great on a low carb bread (which I make myself) evening meal I would maybe have a grass-fed beef steak  (try to buy organic grass-fed meat if possible, the animal will be far healthier and the meat will be too) cooked in butter, with Asparagus and some zero carb noodles. Sometimes I'd have dessert, organic full fat cream with some blueberry or raspberry as low carb treat with high antioxidants and great polyphenol content. I also would be able to stay in ketosis eating a small Sweet Potatoe and Swede (only found this out 4 months into diet) 3 hrs after having meal I often test blood sugar and ketone levels with my keto Mojo Monitor, to see body response to different foods, because everybody’s response is different (keeping blood sugar spikes down is imperative for long term health and staying in ketosis) So on the treats I bought Fattbars, Adonis bars and I just love nuts and seeds most bars are made of them, alon with chicory root fibre and sweeteners, you can also bake some great treats using high fat ingredients and sweeteners (staying away from aspartame/malitilol and sticking to stevia and erythritol. In ride sports supplements you can use waxy maize starch which works well with MCT powder, branded types like Sfuels and UCAN are well respected and used by Keto/LCHF athletes who do long distance racing, these are non-sugar spiking and great ftrom a health standpoint.

Benefits of the diet and what could be seen as negatives

I feel the big change that I wanted was having the ability to be able to go with or without carbs for different workouts and having the ability to do steady state exercise sessions fasted and also being able to deal with longer periods of no food, while not feeling hungry, (which was not possible before) which is good for when fasting/time restricted eating 16/18 hrs) improved energy efficiency and not have to rely on lots of gels while out riding or running. Downsides were when eating out, can be real problem, sure is challenging with choices and obviously wanting to be able to eat different things, I'd often bring my bars and own oils and salt to restaurants. Found the sugar swings were massively decreased but you'll definitely get them when starting the higher intensity workouts because some glycogen will need to be replaced if you’re really depleted. 5 months on the diet I started reintroducing refeeds every once a week or every 4 days depending on session intensity coming up. The biggest downfall for me was how much top end I lost, and this was harder to get back than I thought, at the end of the day I was only doing this diet as in intervention and metabolic upgrade, not for long term which many athletes are making the mistake of doing!!!


The reason this diet is not good long-term, is because our bodies are truly amazing at adapting, but this can be to its detriment, when we take away a substrate like carbohydrate, the body is upgrading fat oxidation and slowly down regulating carbohydrate metabolism, along with enzymes and hormones (bit like training all high intensity and not slow and easy eventually you get diminished returns) so to keep this simple if you look at how we burn energy in simple terms, steady state is good for fat oxidation but when you start chucking in some intensity, and the body has become super-efficient at fat oxidation, the system can be still burning a slower fuel source like fat at this higher intensity, which needs more oxygen!!! whereas when we use the glycolytic pathway it's quicker and more efficient thus needed less oxygen, which would enable maybe higher returns on the work put in. This is all depending on how down regulated your body has become, it’s possible you might not even be able to use that energy system or access it the same as before, I found this out 3 months in I tried to add in some HIIT sessions around VO2max on the bike and run, which is typically around an area where the energy system would be crossing over to more quicker fuel like stored glycogen or exogenous consumed carbohydrates but I couldn't get the heart, lungs and muscles to cope with that intensity, in fact I knew by the taste of acetone in my mouth the body was still burning fat at this intensity and I didn't want that. It was still happening 5 months in while doing 200/400 track repeats, although I was still fast and energy was there, it’s not as good for hitting the higher power and speeds, with that being said my FatMax was very high (fatmax is a term used where the body transitions over to a glycolytic pathway)  meaning I could do high intensity bikes and runs close to threshold but still mostly burning fat, so not such a bad thing if your goal is long distance.

How to get your top end energy system back

I started to research energy metabolism and was also doing a Precision Nutrition PN1 course (The Essentials of sports and exercise nutrition) and I was listening to podcasts with top sports physiologists and scientists, it became obvious that if you don’t use it, you lose it, so the body needed to be slowly nurtured back in to it, by doing some energy priming, these would be short 1min VO2max intervals rather than the normal 4/6min (aiming for 23mins plus in zone) this got me back close to where I was before and my times doing 5k started to come down again and I could get my HR higher to cope with higher wattages on the bike and runs. In hindsight I should’ve done more intensity earlier but felt to weak, this could’ve been avoided if I would’ve brought the carbs back in earlier for refeeds or taken in a carb meal or drink pre session.

How I incorporate Keto/LCHF into my training and lifestyle now

My current method I tend to use now is mainly LCHF for better health as in keeping blood sugar levels down, also fuelling for the required session the right way, eg in the fashion of zone 1/2 I would eat low carb, so abstaining eating any carbohydrate pre session and eating minimal the night before. Mid range tempo zone 3/4 moderate would be moderate carb intake (higher for longer duration or closer to zone 4) and anything higher would obviously be high carb meal 3 hr before or night before. Mostly aiming to stick to 100/150 grams a day.

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