My body outside of cycling lives best on a ketogenic diet - even carnivore.
I know that carbs are the main fuel source for endurance exercise, but I also wonder if there are benefits to switching to fat or protein as the primary fuel. I’ve read some articles and watched some videos on this topic, but I’m still not sure what to think.
Some of the questions I have are:
How long does it take to adapt to a keto or carnivore diet, and how does it affect your cycling performance during the transition?
What are the best foods to eat on a keto or carnivore diet, and how much do you need to eat to meet your energy and nutritional needs?
How do you manage your electrolytes and hydration on a keto or carnivore diet, especially during long rides?
How do you balance your training intensity and volume on a keto or carnivore diet, and how do you avoid overtraining or injury?
What are the pros and cons of a keto or carnivore diet for endurance cycling, and what are the potential risks or side effects?
If you have any experience or advice on this topic, please share it with me. I’m open to trying new things, but I also want to be smart and safe about it. Thank you for your time and input.
as far as i can fathom, your total calorie needs will not change, unless your total energy expenditure changes. your ability to express high intensity will change, if your muscle glycogen levels change. being metabolically flexible means being able to use any or all the fuels, at the right time, to produce your watts. as an athlete, your body will tolerate carbohydrate better than non athletes.
i also believe that excess protein gets converted to glycogen in the liver, which sounds like a positive for us.
i did try a sort of carnivore approach for a while which i really enjoyed but, didn’t cut out cycling carbs.
keto, i suspect is another animal, and not for me.
Yes, there are potential issues including increased risk of afib, stroke, and heart attack. Performance, recovery and endurance will also suffer. As an endurance athlete you would be better off with a high carb / low fat diet. I suppose if you only train 5 hours a week then maybe you can get away with low carbs, but certainly not for anyone training 15+ hours a week.
If you do decide to try it, I would reduce volume and stay at zone 1/2 intensity for at least a week or two to assess how it’s going. Remember, you are going to lose a ton of glycogen without eating carbs, so any intensity will speed that process up.
I’ve not seen/heard any evidence of increased risk of stroke/heart attack caused by eating a Keto diet.
Also isn’t it supposed to benefit particularly ultra endurance?
As the OP mentioned , a keto or high carnivourous diet suits their metabolism, and I think it would be worth them experimenting with the diet to see how it affects their training.
From what I’ve seen ,it may take several weeks/months to adapt to it and you may feel pretty shitty to begin with.
There is a video or podcast I remember listening to about the Keto diet and cycling/running, but I’m really sorry, I can’t remember which it was
You can also experimenting with fueling the workouts with carbs. You can eat a lot of carbs during exercise and remain in ketosis as long as all carbs are used by the muscles at that time. (Probably better to stick to dextrose as it does not need to go theough the liver to be used)
These effects are likely exacerbated by large amounts of cardiovascular exercise, added stress to the heart, lack of glycogen / glucose, reduced recovery, etc.
Most of the studies linking a keto diet to higher heart attack risk are confusing low carb intake (25% of daily calories) and keto (most of the time less than 10% of daily calories).
I’m not saying the increase risk is not true (or false), but I did not see yet a real study on a real keto diet showing it. (but I did not search much)
To OP: it sounds like you are equating Keto with carnivore. I do not believe they are the same.
A good Keto diet does get a lot it’s fats from things like avocados, nuts, healthy oils like EVOO and fatty fish.
Meat does have a place in a Keto diet, but eating only meat to consume described amounts of fat will have other negative health effects often associated with meat consumption.
Keto: A VERY loosely defined diet, but often below 30 carbs but some higher and some lower. Lower carb is the goal.
I am toying with the idea of cycling between keto and carnivore, increasing the carbs as high effort days increase. I failed the last two trainer road workouts and I certainly think this was due to low glycogen levels from near 100% carnivore.
When I started keto, there were 2 or 3 weeks where I just couldn’t do high intensity for long. Then all of a sudden it came back. Just expect it, and do some z2 for a few weeks. If you want to do a hard workout, stick to 30 minutes.
Aside from the induction phase I just described, I’m not aware of any special consideration around injury or overtraining.
Electrolytes are critical. A low carb diet signals the kidneys to remove sodium and you’ll need to work harder to replace electrolytes from sweating. Generally I would just slam a 1/4tsp or more of salt before a workout and salt meals well.
As for foods, carnivore obviously is like meat and eggs. Keto buys you some more flexibility with veg and is a more complicated subject. On rides I wouldn’t worry about consuming carbs. Although on rides up to 3 hours I wouldn’t even get hungry. Often when I got home I wouldn’t be hungry for hours.
I raced cyclocross on keto, and it was fine. Endurance rides were cakewalks. Sweetspot and threshold at or longer than 90 minutes would be a challenge and required carbs during the ride.
check out Paul Saladino. I have followed his recommendations before I started cycling.
the only thing I added was fueling during longer or intense rides. (I use maple syrup and dehydrated mangos)
he started out carnivore and has added specific carbs and has done well…you can see read his full story better than I can type it.
where I’m coming from is: my main interest is health / fitness, not specifically performance for racing or whatever. I’ve also only been training 7 months or so. maybe things will change as I get more powerful?. that’s where I’m at now and I’ve done really well with his recs.
The transcript is a dumpster fire with all the audio inserts … had to listen to the audio to follow it. It seemed like maybe it was being an open-minded interview, but it quickly becomes clear they were just pulling their punches for the intro.
Saladino is perhaps a joke, but I think it was largely a sideshow meant to dirty the whole idea of carnivore by association (not that I want to hear the entirety of their 2 hour interview, but their excerpts weren’t all that powerful). Let’s be clear – he latched onto the idea of carnivore – he didn’t invent it. And I certainly wouldn’t recommend buying anything from him. But that goes for all health influencer types, be it vegan, plant based, mediterranean, USDA food pyramid/plate/whatever-they’re-calling-it these days.
This is an interesting subject to me.
I was cycling pretty serious up until about 2022 and overtrained and just really got into a bad place, so I gave up cycling for a couple of years. I am now back at, but taking it slow.
I will be 59 in September, so I’m an old guy.
Now to the subject. For at least four or five years when I sit for an extended period of time and then get up, my legs hurt badly and I have to move real slow and stretch them out before walking. When I sleep, any time I move my legs, it is really painful and of course wakes me up. I mentioned this to my doctor during my annual checkup and he said what I expected. “You’re old”. lol
Now my wife has been on a carnivore diet since 2021. She tried this after years of trial and error trying to get rid of debilitating migraines and has been migraine free ever since. This is after going to many doctors and specialists and much medication.
Well since I live in the same house, the easiest thing for me to do was give it a try. Besides, eating steak and bacon almost every day is not torture. lol
After several weeks of it I one day realized that my legs no longer hurt at night and I could sit at my desk for hours and then just jump up and run if I wanted with no pain.
I have not studied any on this, but I am guessing it is an inflammation thing.
Then when I got back on the bike, I decided to get back on carbs to help with my performance and sure enough, almost instantly my legs started hurting again.
I say all of this to say that I understand it when the OP said that his body lives best on a high protein diet and I would love to be convinced that we could eat this type of diet without performance suffering.
i mean…are you pro? who cares if your performance suffers if you are healthy overall and enjoying the bike.
eat carbs and FTP is 15 watts higher. don’t eat carbs and live without leg pain. not a hard decision imo.
what I did was stay carnivore for quite a bit of time…then sloooowly added carbs one food at a time to see how I reacted. (this was before I started to cycle…but I was weight lifting and hiking - fairly active I’d say).
then when I started to cycle I just increased my carb foods that I knew my body was good with.
yeah I’m never gonna eat anything on the bike that I wouldn’t eat off…never. and I am gonna live with knowing I won’t reach max performance. I’m still biking quite a bit…~10-12 hours per week all year and ~15 hours per week the last 6 weeks or so. numbers are going up and i’m in decent shape and sleep good and never get sick, etc etc.
that’s just my take fwiw.
ETA: I do eat quite a bit of carbs now…but like I said even on bike it’s all food (dehydrated mangos, maple syrup, figs). off bike I also eat a bunch of other fruits and white rice and honey. carnivore is my foundation though and it works great for me.
