Just out of curiosity, does anyone here ride and train while on a low-carb or ketogenic diet? The idea intrigues me because I feel that something like a TKD (targeted ketogenic diet) should work for a recreational (ie, non-elite) cyclist but I'm struggling to find any real or anecdotal evidence of any quality to support this.

In the interest of full disclosure, a few weeks ago I finished up a massive block of summer training (southern hemisphere) targeted at endurance races (100km mountain bike races). With that behind me, I'm now getting ready for the track season, so back to the weight room, intervals and a lot less volume.

This is the first chance in a while that I've had to follow a really aggressive diet for a few months so I've taken the opportunity to commence a TKD in order to strip off ~5kg and get down to my ideal race weight. a TKD sounds to me like a reasonably easy way to do it from a diet perspective and since most of my work in the next few months will be shorter rides, or weights, it shouldn't impact my workouts as such.

Not really looking for quasi-scientific reasons why i shouldn't continue with my diet or "why don't you just use a conventional diet?" - I have no real goals for the next few months except for losing this stubborn weight so I'm going to continue on regardless. If it doesn't work then it will be an interesting personal experiment. I am however very interested to hear the opinions of anyone who has tried something similar in the past, or does it on an ongoing basis.

Also, if anyone's remotely curious, let me know and i can post some day to day reports as to how i'm going, what i'm eating, training sessions and response, etc.

Thanks

Well I can give you a scientific reason, the brain runs on carbs.

Long term damage is not yet clear and has been used deliberately in the medical fields for very specific ailments. There are clear short-term risk if not managed clearly.

Inducing ketogenesis for any prolonged period of time is just a stupid idea and I wish to put the caveat for all who may be thinking of following a similar plan to consult with an endocrinologist and get their take on prolonged, deliberate ketogenesis for exercise.

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You can go for hours on a very low carb diet at low-mid intensity riding, coupled with some caffeine. Your recovery, however, will suck, I can say this out of experience.

I'm presuming that you've read Lyle McDonald's literature. If you are going on a TKD, you should budget for more than 5kg of weight loss before ending the diet as you'll gain a lot of the weight back in the form of fluids attached to carbs when you start eating normally again



Only partially true, the brain can get up to 75% of it's energy from ketones, the other 25% can be obtained from fats, broken down to glycerol, serving as a substrate for gluconeogenesis. Some amino acids can also be converted to glucose so, very little, if any, dietary carbs are needed under normal circumstances.

I would suggest at least a week of short, low intensity rides when starting the diet, then increasing the duration gradually. Actually, I would also suggest at least a sports drink whilst out training, or sugar water. Work out how many calories you'll burn and replace at least 50% of them in the form of carbs whilst on the bike. Consider this your only source of carbs. At the worst, you'll interrupt ketosis for a few hours.

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K2

Do you suffer more when you train, or cannot train?

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Yes, the body functions without carbs. An excellent survival trait. But not one that could be called ideal or optimal. Gluconeogensis is a really cool thing though, as are most of our metabolic pathways, but carbs are still highly preferential for muscle and brain function.

_________________
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG

Totally agree, IMO, anyone who does any form of training should consider dietary carbs to be their primary energy source. Ketosis occurs to a small extent for short periods of time in everyone but, it certainly wouldn't be my preferred solution for weight loss.

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K2

Do you suffer more when you train, or cannot train?

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I wouldn't do it.

I haven't read Lyle's book on Ketosis in a while but isn't the transport of FFA by L-Carnitine the limiting step in Ketone production? For short intervals of weight training I think it would be Ok but for anything cardio related?

When I was on Keto about 4-5 years ago I was playing a game of Tennis. About 45 mins I felt amazingly horrible... like a bonk only different.

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Great way to strip off your form too. If you want to do it I would be looking to strip 10 or more KGs. Then start again.

What is the obsession with stripping weight? On the track, weight should be the least of your concerns.

I would also like to see a gorilla or two return as GC contender. Show them.

I have done it several times for various reason with success. Several caveats have been mentioned above already. If you want to do this for weight loss exclusively, which is the only reason under the sun I could possibly see doing this for, you want to do low intensity works out ONLY. Even then, you WILL need to consume some sugars during the work out. That is, unless you plan on going out and not get your HR >120. If you drink something like gatorade for example, it will provide you with some needed sugar but it will not be enough that will screw up your ketotic state.

The worst downsides to this system have been pointed out above, but I'll give you a couple again:

1. forget form and intensity. You'll have endurance, but speed will be flushed down the toilet.

2. You MUST, and let me repeat ti again, you MUST drink around the clock like it is going out of style. Literally, if you are not going to the bathroom to pee every 30 min or so, you are not drinking enough. That is also around the clock, which is a huge hassle in itself at night. Personally, I used t drink about 16 oz right as I went to sleep, and kept a pitcher full next to my bed. When I would get up to pee at night, I would drink another 16 oz before I went back to bed. You'd be surprised how used to it you get

3. 2-3 very intense rides you should rid you of most carb storage, so if you go nothing but protein and fat in the diet from day one, you should be ketotic in 4-5 days. Best way to find out is your breath starts to stink big time. Start the drinking on day 1.

4. no alcohol of any type.

5. No speed or intensity. You will feel like chit on day 3-5 while you turn over to a ketotic state. Headaches, nausea, and feeling weak is normal. After about day 5, you really won't be hungry either. Not "physically hungry" at least. Mentally though, you may still be hungry the entire time. Hunger/food is an addition like crack, caffeine, or any drug. That may never go away, but it should get much much lower. Once you get over that hump, you are golden and feel very energetic actually, which makes it even more difficult not to go and try do high intensity stuff. Even if you do though, you'll soon find out you can last more than a couple of minutes LOL......

6. This is obviously a tool, not a way of living. Same like any other diet really. Once you loose the weight and go back to a normal diet, it will take you quite a while to gain the weight back as one of the benefits of the ketotic diet is the very depressed appetite. You won't be as hungry and your meals will be far smaller when you do eat and get hungry.

As much as it has worked for me, it is not something I would advocate for anyone given the risks involved. You are past the talking you out point, so be careful and let us know how it goes.

hey guys, thanks for all the comments.

before i go any further i feel i should clarify what i'm doing here:

1) this is a TARGETTED ketogenic diet. by definition, i break ketosis and hit the carbs in order to complete my "workouts". when i'm on the bike i'm sipping on carb based sports drinks and/or chewing on carb based foods - i'm not training in a fasted state. i have read protocols for grams of carbs per set of weights while on a TKD, but i've seen nothing for carb requirements based on time on the bike or running and nothing relating to intensity, so this is something that i'm experimenting with to devise a repeatable protocol for myself.

2) this is a LOW-carb, not a no-carb diet. my baseline for carbs irrespective of workouts is about 40-50g.

3) I'm not doing any real endurance training at the moment - my weekly training is basically 3x weights (essentially a full body rippetoe program), 2-3x intervals (vo2 and LT sessions) and 1 or 2x road rides around 2hrs (i need to be on the road to do my 5-15s sprint efforts plus it's nice to ride somewhere other than in my garage for a while too).

Worm: cheers for commenting, I knew you would have something interesting to say. I have read opinions and assessments from people on both side of the fence regarding the impacts of ketosis on the brain, I am aware of the risks and I am comfortable with them especially considering my baseline level of carbs. I am also of the opinion that much more long term work research to be done in this area.

kevin: thanks for the info. yes, i've read a lot of lyle's blog posts, but not his book.

horse: yes, that is the target. I want ~5kg net but to do that i know i need to lose ~10kg total to account for fluid loss which will come back as soon as i resume eating carbs. I'm not expecting much if any muscle wastage as i'm doing work in the weight room and keeping my protein intake up. too much protein and not enough fat may have impacts on my ketosis, but it's something that i'll need to observe and optimise over the next few weeks.

I'm not trying to drop weight for the track specifically (though i still need to get every gram off the line and accelerate it so losing weigh will still be somewhat beneficial), this is a long term thing that will hopefully see me carrying less kilos up the hills next summer.

dgasmd: 1) over longer rides, i have already accepted this. i am hoping to see an improvement on my L5->L7 though as i haven't worked directly on those systems in a while and i am at the moment. watts/kg should also improve due to kg going down.
2) yes, definitely. i'm going through about 4L/day at the moment.
3) done.
4) http://burleighbrewing.com.au/beers/bighead/ 1 of these on the weekend is an acceptable cheat to me. is there anything about the metabolism of alcohol that may disturb ketosis that you know about?
5) "keto flu" passed in the first few days. I had brain-fog for a few hours one afternoon last week (day 3 i think), but that was it really and now i'm really enjoying the feeling of being in a ketogenic state.
6) agreed. if i didn't exercise at all i think i could handle this diet on an ongoing basis, but when i return to endurance training i will certainly be waving goodbye to it.

When i find some time over the next few days I'll post some observations and comments on my progress so far, but it has been generally positive so far.

Hopefully this is helpful...

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