If you’ve not seen the previous blog posts I’ve written on my thoughts and experiences on a low carbohydrate diet, then this would be a good time to check them out! I’m going to go into some depth in this post so if you’ve landed straight here you might be better to come back after reading these:
So….before we start I thought it might be useful to define some terms I’ll be using or you might have come across in case you are not familiar with them. If you are, skip ahead!
(Nutritional) Ketosis – the state your body is in when it is producing ketones (above a certain level). Usually achieved by restricting carbs to between 30 – 50g per day (could be more or less depending on the person and their level of exercise volume & intensity)
Low Carb High Fat Diet (LCHF) – any diet where carbs are generally restricted & replaced with additional fat (protein stays the same), but without the carb restriction down to the levels to promote nutritional ketosis.
Ketones (or ketone bodies) – a by product of burning fat (so the more floating around your body the more in ketosis you are)…and the preferred fuel for your brain when in a depleted carbohydrate state
(Diabetic) Ketoacidosis – a bad thing! An condition potentially affecting diabetics when blood sugar and ketone levels both get dangerously high (not possible in non diabetics). Related to but not at all the same as ketosis…if someone tells you ketosis is dangerous then they are probably mixing it up with this.
Keto Adaption – when your body has been in nutritional ketosis long or often enough, and has produced sufficient enzymes to increase fat utilisation levels & your muscles have become efficient at using these increased levels of fat as fuel. In real tems you are at the point where athletic performance returns to ‘pre ketosis levels’ Around 1 – 2 months as a rough estimate, but probably varies based on how ‘strict’ you are with keeping the carbs low.
Keto Flu – the flu like symptoms when first entering into ketosis. Your body & brain’s way of saying wtf do I do with this new fuel, and where have my carbs gone??? Usually over within a week or so, depending on how hard you reduce the carbs down. Symptoms are often made worse due to lack of hydration & low sodium levels.
Z1, Z2, Z3, Z4, Z5 – nothing to do with ketosis or diets, but shorthand for training zones as defined by Andy Coggan. Z1 is recovery pace,Z2 is endurance levels, or steady riding, Z3 is tempo (think challenging group ride pace), Z4 is threshold, and Z5 VO2 max. Roughly. There is more to it than that, but hopefully you get the idea.
I’d also like to state that while I’ve learnt a lot about low carb diets and ketosis over the last 6 months and the effect it’s had on my own athletic performance, I’m not an expert and definitely not a doctor. If you are thinking about trying ketosis or a low carb diet out, I would very much recommend it (you’ll see why just below!) but I encourage you to do your own research, and if you have any existing conditions then to definitely check things out with your doctor or a medical professional. Keep in mind though that while ketogenic diets are getting more popular they are still very much contrary to the ‘traditional’ nutritional advice so the response you get may not be 100% positive, but use it to make you own mind up along with whatever research you have done into your own personal circumstances to determine if it’s for you or not. Get out clause / ass covering over 🙂
So, before I get to the question you want hear an answer for, why should you consider trying out ketosis? ie what will be the positive effects?
- Potential weight loss, while not affecting energy levels for effective training. This is a big one! Balancing hunger, calories, energy levels and a training schedule on a traditional low fat high carb diet is a nightmare….on a low carb high fat diet it’s a relative piece of cake!…but you can’t eat the cake… 🙂
- Less reliance on high carbohydrate energy products (which cause gastric problems for a lot of people, including myself)
- Ability to exercise for long periods with minimal fuelling…less chance of bonking / hitting the wall etc
- Concentration levels can be maintained for longer…no brain fog from being in a low blood sugar state
- Consistent energy levels throughout the day
- Feeling just as full of energy after a long ride as before it! For example not needing to crash out on the sofa after getting back from a tough ride…handy for anyone who’s not a professional athlete.
- More consistent mood
- Better quality of sleep…another big one. I personally think sleep is the most important aspect of recovery, and recovery is often woefully neglected
- Less oxidative stress for a given level of exercise (compared to when consuming carbohydrate energy products)…this means quicker / easier recovery as you do less damage to your body in the first place
So, this sounds great huh? Of course, as with pretty much everything in life, there are two sides to every story. Here are some of the things that aren’t so great about the diet:
- Learning what you can and can’t eat – as this is probably a big dietary change for most people, it takes time and effort to discover and learn new recipes, buy in all the different products you’ll need, and unless you live alone or convert you whole family you’ll probably be cooking two separate meals each time you eat (or at least cooking one meal and adjusting yours to include more fat). There are plenty of resources out there to help however, and this is a good one to start with.
- Following on from above…..Social eating. It’s possible but not always easy to follow a LCHF or keto diet while out at a restaurant, and I wouldn’t even try if I was invited to someone’s house for a meal (although of course it’s probably ok to ask if you can pass on the potatoes).
- No more beer….or French bread…or ‘insert your favorite carbohydrate rich product here’. As you are either in ketosis or not, you can’t ‘cheat’ with this diet, and definitely not in the early stages. In one way I think this is a good thing….sugar is remarkably addictive and it took me a good couple of months before I didn’t feel the urge to eat something sugary whenever I saw it. However now I look at a piece of chocolate in exactly the same way I’d see a big chunk of cheese…it’s just food. It wasn’t like that 2 weeks into a LCHF diet I can tell you! But tough it out and it will be worth it…
- Your cholesterol levels could increase. This is a complicated subject, so I’ll just say that for most people cholesterol improves…as shown by this study, but for a small number (myself included) your total cholesterol levels can increase. I’m not personally concerned however, as my ‘good cholesterol’ (HDL) has increased, my triglyceride levels are low and while my ‘bad cholesterol (LDL) is higher than I would like, it’s the particle size that matters, and LCHF diets typically increase LDL particle size (which is good)…..so if you are still with me I think I’m going to be ok!
- Aside from dietary implications, you might lose your capacity to exercise at very high intensities, such as sprinting, or short efforts above VO2 max for example. Early on in the diet, when you are still adapting, anything above tempo (a strong effort but not really fast) feels terrible, but then as time goes on everything goes back to normal…with a little bit taken off the top end. Having said that though, this study showed that long term LCHF athletes had just as much glycogen stored in their muscles and replenished it at the same rate (despite not eating carbs) as the high carb athletes….so you might be fine!
So if you’ve got to this stage and think, yes, on balance sounds good, should I try it out? Then I’d say absolutely, give it a try. Especially if you are:
- a long distance athlete (ie take part in events that take 4 hours or more)
- are struggling with carbohyrates, or have the feeling that they are doing you no good
- have swings in energy levels or mood (ie do you often feel you would like to take a nap early afternoon?)
- would benefit from losing some weight, but don’t want constant hunger and lack of energy
- not someone who needs a race winning sprint
If you’d like to learn more about ketosis and the effect on sporting performance, I’d really recommend this book by Volek & Phinney. They are at the forefront of science in this area.
Now I’ve covered the bigger picture, how is it going for me? The last blog post I wrote was just before Christmas, and I wasn’t convinced I was going to get through without being tempted back to the dark side (my traditional high carb diet). It went remarkably well however, and while I did of course eat many things that meant I was nowhere near ketosis, I generally stuck to avoiding the high concentrations of carbs (except for the odd desert!) and then afterwards settled back into a LCHF diet, a bit more relaxed than the ketogenic diet I was trying to stick to prior to Christmas. This worked well for me in the off season, especially as I wasn’t doing much exercise at all (our new project kept me off the bike for most of Jan – April). However I decided to try and get back into Ketosis in April, to see what effect it would have on the long rides I typically do when getting back into base training.
The first thing my engineer brain thought was ‘well how can I measure that I will actually be in ketosis?’ Some people are happy to restrict their carbs and, quite rightly, assume that they will be in ketosis. But being a precise kind of guy, I have to know!
I’ve used Ketostix before – which are great when you start out, but less accurate as time goes on (they measure the waste ketones in your urine, however after you become keto adapted your body disposes of less and less of them…as it finds a balance on how many to produce, and the body becomes more effective at actually using them as an energy source.) I thought that my 2 months keto and then 3 month LCHF would potentially make them useless.
An alternative is blood monitoring. Using the same device that diabetics use to measure blood glucose levels, you can buy strips specifically to check your blood ketone levels. While very accurate, they cost a fortune! So I plumped for option 3….
A Ketonix – a device that measures the acetone (another by product of ketosis) in your breath. The advantage of this device is that it’s a one time investment – no strips required, so you can test as often as you like! It also tells you in real time how much you are in ketosis (the blood test shows you how long / much you have been in ketosis as the ketones in your blood are effectively an energy storage facility by your body, but you could have a high value, eat a doughnut and be out of ketosis while still having (temporarily) high blood ketone levels). Therefore using the breath test method (Ketonix) you can in theory find out which foods might kick you out of ketosis, how many carbs you can eat after exercise while staying in ketosis, etc etc. Sounds perfect! Unfortunately, my Ketonix doesn’t work.
I know this as after many weeks of trying, and sticking to 30 – 40g of carbs per day, I still wasn’t getting values showing I was in ketosis, and often getting a zero reading. So in the end I bought a blood monitor anyway, which over the period of a week showed I was definitely in ketosis, while the breath monitor was still showing me a big fat zero.
So, after an email to the vendor, I have a replacement on the way which with fingers crossed will work this time! Note there is a common mistake made by people using the Ketonix regarding the breathing technique….it needs the very last bit of air in your lungs, which can be hard to get right. I was literally turning my lungs inside out however (I once got cramp in my intercostal muscles I breathed out so far!) so I’m fairly confident I didn’t make that mistake.
Measurement aside, the diet is generally going very well for me. Compared to my last update my cycling performance is right back to where it should be…perhaps even better – which I’ll talk about more later on (better compared to a high carbohydrate diet, and for the amount of cycling I’ve done so far this year). The sluggishness I sometimes felt in the early stages of the diet before or during exercising is gone, and now I’ve done some longer rides (just with electrolytes) I can clearly state that energy levels are not an issue (the legs on the other hand need a little more work – I’ve not done much riding yet this year compared to normal). One key factor I feel has really helped get the most out of my performance on this keto diet, is ensuring I am getting enough salt prior to exercise. It’s another aspect of the diet that is ‘against current advice’, but when in ketosis your insulin levels are very low, and it’s insulin which signals to your body to keep hold of salt. So in ketosis (or for a lesser extent on a LCHF diet) you need more salt to compensate for the fact that more is just passing straight through your body. Having your sodium levels wrong can create havoc with your endurance performance (low levels will restrict your blood volume as your body tries to keep the concentration in a certain range). Obviously if you have high blood pressure already you will need to be careful about this, but if not, I’d keep adding salt to your diet based on feel. A drink made from a beef stock cube will really boost salt levels, and if you have one of these an hour or so prior to exercise it can really make a difference. Salted mixed nuts are now my cycling ’emergency snack’ rather than gels or bars, which I’ll occasionally take a small amount towards the end of a really long or tough ride.
Another good tip which can give an energy boost is the use of MCT oil. This is oil that has been refined (yes I know processing is not good) to just leave the medium chain triglycerides (C8 is the best, followed by C10) which are most efficiently used by your body during ketosis. I’ll typically have this in the morning with butter in my decaf coffee – look up bullet proof coffee…you can use real coffee for an extra fat burning boost…I’m just not very good with caffeine unfortunately. Now I’ve been in ketosis a while I seem to digest it pretty quickly, so sometimes have one 1/2 hr or so prior to exercise for a boost in energy levels. Normally fat prior to exercise is a bad thing as it’s difficult to digest (if you are on a traditional diet), but I think the combination of the medium chain oils and being keto adapted means it goes down just fine!
Other potential energy sources that I’m yet to do much experimentation with (but it’s in the plan) are:
Exogenous ketones – these are synthetic ketones (exogenous means produced outside the body) which are usually sold as a dieting aid…but potentially give a big increase in blood ketones hence energy levels
Vespa – a really interesting looking product that stimulates your body to produce more of it’s own ketones (using peptides extracted from wasps!) I’m keen to try this one out – if it’s good enough to help Romain Bardet win a stage and come second overall in the TdF then I’m willing to try it! More to follow on both of these…
So to finish (sorry for being a tease :)) I’ll get to the original question..has being on a keto / LCHF diet made me a better cyclist? Well I did a training ride the other day that’s a standard ‘long-ish’ test for me – 100km (give or take) with just short of 1600m climbing. I went pretty hard, especially given it’s the first time I’ve done it this year. Rather depressingly, power numbers while climbing were well down compared to previous years, but I did expect this as I’ve done much less riding this year – about 80 hours so far this year compared to about 180 at the same stage last year…and much less higher intensity work. So that was to be expected, and I did wonder if I was setting myself up for trouble – going hard, longer than usual, first time of trying this year, not enough miles in the legs…all the standard ingredients in a recipe for disaster called bonking. But I continued to feel ok so kept going. One thing I did notice was that despite the lower power, the lower weight meant that the climbing speed wasn’t too bad, but it was the sections in between where I’d typically have to back off (my normal thinking is there’s no point burning your matches when on a carb based diet on the flats…you want to save more energy for the climbs) where I felt that I could still keep a relatively good pace…and it didn’t appear to be affecting my overall energy reserves. It felt like an upper zone 2 endurance pace, which before I changed my diet I could keep up for a long time but would ultimately be using some of my energy at a slow rate, was now free! This is possibly because the diet has bumped up the intensity I can ride at while still maintaining 100% fat burning…I’ve no idea of the numbers as I’ve never done the relevant testing but my guess would be that in the past, even when fit I was probably something like 75%/25% carbs vs fat at that intensity (upper Z2), so even though 25% of not much is not a lot of calories burnt, over time it still depletes your glycogen reserves. Riding on the flat or downhill at this pace felt just fine even at the end of my ride, where typically everything normally feels bad (just different levels of bad!). During the second half of the last climb of the day I did feel like I was starting to lose strength, but 20g of salty nuts later I felt much better. Whether it was the salt or the carbs (I’d been riding between Z3 & Z4 on the climbs so will have been using glycogen) I don’t know, but it picked me up and I finished feeling pretty good, especially for the effort I’d put in, and the fact that I’d gone way harder than usual for a first effort of that type for the year. So how did I do? Well despite the fairly poor power (which gives me something to aim at improving), and lack of training hours I got round in a shade under my best time ever….which pretty much blew me away. I was purposely trying to avoid carbs during the ride in order to test myself, but would not do this in a race situation so even with my current relatively poor level of fitness there is scope for improvement. I was riding alone so there was no drafting effect, & given the amount of climbing the weather / wind doesn’t come into it too much (although weather conditions were pretty good, so this might have helped a little). I was probably also unconsciously pushing a little harder maybe (as I wanted to be faster) but seriously didn’t realise until near the end of the last climb that I was on for a good time.
So, for one test in my own personal n=1 experiment, the result is a (totally unscientific)win for ketosis! Perhaps a little more testing needs to be done :), but it’s started in the right direction.