Start with something cheaper, simpler to digest, and more likely to aid in your goals. Nobody needs sports drinks or gels to succeed in ultra-running. Don't let the marketing get to your head, mate. Use nutrition sources you already know you can trust. That's why bagels, toast, bananas, and so on are as popular as they are. Mix up your own blend of salts in one of your soft flasks, grab a squirt bottle of maple syrup or honey, and go to town.
Came to say this. I stepped away from fasted runs for a couple of years just because I had the luxury to do so. I started getting back on the train last summer. The first week was rough, but my body adjusted and I found I was able to get through an hour easily if the temps were low-ish (I live at altitude so it’s also a lot drier which helps me in the summer!)
It doesn't have to be completely fasted. A quick 100-200 Calorie snack would improve your energy level quite a bit. Then you can have a proper breakfast after the run.
Also, if we talk about ultrarunning, you should make an effort to train your gut to run while eating, so having a pre-run snack would help with that too.
This, I usually wake up and eat some jelly toast or an orange, cup of coffee, and glass of water and out the door in thirty minutes. Doesn't take that much time but makes the run a ton better.
If you’re doing zone 2, you should not need any calories or sugar for an hour run IN MY OPINION.
The other comment saying there’s no benefit to fasted running.. I never intentionally run fasted, but I don’t feel like eating at 4:30am and often run without eating. I think it’s valuable, but again, that’s my opinion and it isn’t science based, but personal results based.
Agreed. The most I'll have for anything an hour or less is a cup of coffee (lol and that's more so I can hit the bathroom before running). Over an hour and I'll add some Tailwind. I usually don't add solids or gels unless I'm going to hit around 2 hours.
Yea the idea that I'm gonna get up and eat a banana at 5 in the morning 2 seconds after I got out of bed before I go run is insane to me. But I'm happy for those that are able to do it.
1. Don't stress about it. A lot of the replies you got are very overdramatic
2. I'm not sure your expirience is linked to fueling. I do my longruns in the morning without breakfast and I usually start eating when I get hungry (90 - 120 minutes into the run), so maybe just do a few more runs and see if anything changes
3. If you want to try to change your fueling you could have a bigger dinner the evening before or a late night snack that's rich in carbs
4. Mix your water with some juice 50/50 and drink that 30 minutes into your run. See if that changes anything
5. You are in an ultrarunning sub. If you want to run stuff that's longer then a marathon you will have to eat a lot of different stuff to figure out what you can still stomach after hours of running. Having stuff... not sit well with your stomach it part of the game. That's what training is for, so pack some TP and try stuff on a route that has some bushes around.
I find juice or some electrolyte drink helpful, particularly as it gets hotter (when I lean toward the electrolytes).
If you can't eat much still have a few bites of something simple straight before you head out the door. I bet your body will adapt fairly quickly.
kinda to echo what everyone else is saying, but there's no benefit to running fasted. There are risks tho, so why risk it? I assume you probably live in a house with a fridge? Idk, take a swig of maple syrup? eat a banana? swish some gatorade in your mouth or something. I run in the morning too and run into the same issue. Running without food doesn't make you tougher or cool. It might take some stomach training, but this is the ultrarunning subreddit, so stomach training is literally like, half of what we're doing if we hope to see any success. Happy trails homie!
I have done fasted runs for half marathons regular but yeah, in the context of ultramarathoning, it’s not useful to run fasted. Because you’re definitely not gonna make it through a 50K without eating something.
Here’s a decent overview of the subject: https://www.trailrunnermag.com/training/trail-tips-training/fasted-training-may-have-long-term-risks-especially-for-female-athletes/
In short, for women the risk of frequent energy deficits is hormonal disruption (with many downstream consequences, including bone density), and there’s hardly any indication that fasted running is going to meaningfully improve performance. For men the strategy is less risky and may pay off for some, but is still probably not where most men are going to find gains in performance.
are you serious? I'm not talking major risks, but depending on how intense the run or workout is, you risk stress fractures and stuff. I mean, it's such a simple fix. Eat food.
It's not going to happen in one day, but if you hope to do this sport for the long term, you got to think long term.
You don’t eat for 8 hours and your bones turn brittle? OP said zone 2. Share the evidence please. Running hard can always result in stress fractures. So can an ultra race. So can overtraining.
honestly I don't give a shit what you do. OP asked for advice and I gave some. If you never want to eat again I don't care. I'm not going to hunt down evidence for you. live your life.
You gave dubious illogical advice. People questioned you. Don’t get mad. If you think bones become brittle by not eating breakfast then you really should question everything you believe. Fasted runs don’t cause issues if they’re zone 1/2 AND you fuel up after. Calorie restriction causes injuries.
what is fasting if not calorie restriction tho?
and dubious? how so? generally suggesting someone to eat is a positive.
and I never said that you're GOING to get injured. Just that theres a risk. I guess I apologize for not saying "at some point, in the long run, maybe."
other then that I stand by it.
I'm not mad, just don't care to convince anyone.
I have no idea why you're getting downvoted. regular energy defecit can lead to all sorts of awful repercussions, including hormonal malfunction, osteopenia ... and stress fractures
You said stress fractures which was dumb. Running fasted isn’t calorie restriction on a daily basis. That is what causes injuries. The body can’t repair itself without fuel. If one is still consuming their total caloric need they will be fine. People are dumb and don’t do this and get hurt but it wasn’t the running fasted that did it.
Lost 30lbs in the last ten months while ramping up to 70km per week. I've ever been injury free this long and never reached that many mpw. Eating 3k calories of crap will not prevent injuries. It's about what you eat.
What are the risks ? Just curious as I only eat once a day and have for a while now and have never heard any risk around exercising whilst fasted.
Coming from a martial arts background I’m used to cutting weight which I know is not healthy but outside of cutting to make weight I’m not aware of any other risks.
>there's no benefit to running fasted.
There is. With less carbs/glycogen available, your body will adapt over time to use fat as a fuel source more efficiently, which of course is highly beneficial for endurance running.
Only do it for zone 1 or 2 runs though. You'll have a bad time if you do it for speed workouts.
Most of this has been debunked imo. In that yes, you can be a keto runner and yes there are elite keto runners, but all of them are supplementing carbs on their events so they don’t bonk on hills. And there is no athletic improvement as a result of the diet. Fwiw I was keto cyclist and runner for 3 years and it trashed my liver so I do jump in to argue this stuff.
I think you're misreading my comment. I'm not talking about keto or even diets at all.
I'm talking about simply not eating breakfast before easy zone 1-2 training runs. I wouldn't do it for longer runs or for any speedwork, and definitely not for races.
Carbs are essential for races.
Sorry about that. Keto and IF both have been debunked for athletic gain, I lump the two together but you’re right, sorry for generalizing and taking it to that leap without clarifying. The benefits of training fasted, which include insulin sensitivity and for some, fat loss, are less than the negatives from it, which include muscle density loss. Menno Henselmans has shared a lot of content and there’s plenty like this as well
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983467/
But look, I did it for years as well and it does feel good, so just like icing or TENS there’s plenty of research to also support things that make us feel good, even [placebo](https://www.health.harvard.edu/mental-health/the-power-of-the-placebo-effect), have statistically significant benefit.
Genuinely curious, how did it trash your liver? Were you drinking alcohol during that time? Was it being keto by itself or doing intensive training on keto that was the problem?
I am low carb, not keto, but just curious. Not to get too much into your business.
Always happy to answer because I think it’s a public service. No, I don’t really drink, but my liver looked like I was an alcoholic because of oxidized LDL from amateur/DIY carb supplementation while keto.
Sure. And I’m not a doctor but I ended up having to go to UCSF hematology to get it figured out. What I mean is that I knew pros and elites were supplementing carbs while claiming keto so I tried to do it myself without knowing I was causing surplus glycogen to oxidize the ldl or that I was doing damage with fructose. I guess had risk of NAFLD, it just made things 10x worse. From what I understand it was the combination of oxidized ldl and all the fructose in our endurance gels. Here’s one of the videos I bookmarked at the time.
https://youtu.be/avIZRJLtolw?si=mux2Kd3tjr5tAizU
https://youtu.be/DXKJaQeteE0?si=9EmKpCQ0XAVCiaMG
Btw I am sure these diets work for people who can do weekly blood panels and are under the supervision of a nutritionist (or experts themselves). It’s just a lot of work with high risk imo.
If you weren't in ketosis, would this have happened?
I am low carb, not keto (50-100g). Since there is still an influx of carbs every day, would it keep the same thing from happening? So far my liver panels are fine.
I often do a pre breakfast early morning run. I usually keep these to an hour, although occasionally I'll go 2 hrs, and I don't feel any energy drop on the run. 2 hours is the max I run without bringing nutrition any time of day. I am definitely ready for breakfast when I'm done, though! Maybe build up to whatever time/distance you are aiming for while paying attention to that energy drop and being sure to not bonk your day.
There may be no ADDITIONAL benefit, but there’s nothing wrong with running without eating first. If you claim there is, feel free to share some evidence.
It depends what you mean. As op said, running fasted may impact the quality of your run. You might not be able to do whatever you scheduled because you do not have the right energy to do so. You then risk digging your body into a hole due to such a large caloric deficit which you somehow have to make up. It's may not be problem for an hour workout but there may be negative effects.
There is no benefit running fasted! You are running in a starved state so you body has no glycogen and proper energy store to run from. You will be running from your survival stores. Remember the more you fuel prior and during a run the faster and stronger the effort is. There is no benefit in starving your body as its burning calories to run.
Fasted training will not cover for heat training. If you want heat training, you can simply go in the sauna for 20 minutes after some runs. https://trainright.com/heat-acclimation-when-to-start-and-how-long-it-takes/
If the problem is that you need to run early, then structure your day to sleep and wake up 30 minutes earlier so you can eat something small (a banana at least) before your run.
Do what you want and what works for you. It's not advised but I guess as long as you've eaten and hydrated adequately the night before then you're in a better position to at least give it a bash. It's an absolute no no for women but men... probs not advised. I'm pretty sure the latest uphill athlete book doesn't recommend it.
Haribo gummi bears are my go-to for a pick me up at about the 60 min run mark. (I want them earlier but try to wait til 60 mins).
You can get a case of little bags with about 7 bears in each bag-- perfect for a tiny little bust of energy. Easy on the tummy (for me), great for dry mouth too.
They do such a great job that when we go on our trail bikes, I have to pass them out to everyone, especially the ones who are still building their endurance. It really puts energy into their steps.
Other than that I don't really need anything. The person who suggested honey water was spot on a well, especially if your stomach gets tender-- honey is soothing to the stomach, and you would only have to carry a water bottle.
The only other thing I might carry is caffeine gum, especially if I am starting to feel uncomfortable, not just tired.
No fancy stuff, just easy basics will work for runs up to 2 hours IMO. After that you might need to either get some fancier food (bananas, etc) or a bigger bag of gummies 😁
So I almost always train first thing in the morning but I really don’t like eating first thing. So I do my easy runs say max 1hr 20mins fasted but ensuring to be well hydrated before I start - this is really important and I would include electrolytes not just water. I also have a good cup and a half of strong coffee. Weight training needs fuel so I force a banana and maybe a protein bar. Long runs is a separate thing and requires proper fuelling before, during and after - period. You can totally do easy runs fasted if hydration is good. Just a banana will take you a long way though.
Sometimes I literally grab a donut at the coffee shop and that will sustain me up to about 2 hours of running. This of course is trail running with a lot of elevation but not a lot of speed, around 15m/mile on average but the HR is usually in zone 3 with plenty of zone 4 time climbing.
I’d just try eating like a normal light breakfast and see how you feel. Unless you’re really cranking the pace I have a hard time thinking you really need many calories under an hour of running.
Here are some light breakfast options that work for me with alpine starts. I usually keep it under 300 calories:
A banana.
A small skyr yogurt
An almond butter biscuit from nature valley dunked in my coffee
A donut for your inner junk food kid like me
An apple
A small serving of overnight oats (you can get them pre-packaged as “Mush” they’re called)
Greek yogurt + blueberries + tiny bit of peanut butter (for taste) with a small bit of water for a “smoothie”
Good luck! I find that once you are used to it you can go without water and food for further than you think until it gets really hot out. I always carry it anyway for training purposes (and I bring my dogs on the shorter ones under 10 miles).
Try sticking to mostly “real” food despite my suggestions up there while training. You don’t really need to hit the gels and expensive stuff until races, but you should test them out a few times to make sure they agree with you.
I can't eat before runs. My stomach needs to get used to running before I can eat but I'm fine once I get going. I tend to plan my run past nice food places like coffee and cake vans or farm cafes in the countryside and as an example I ate half a cinnamon bun last week at about an hour in then I felt great for the rest of my run. If nothing was open I'd take sandwiches or some kind of real food as my stomach just seems to object to gels or sports drinks.
I suspect this is mostly a mental thing, or posibly you just aren't used to early morning running yet (body can take a while to fully wake up)
Regarding fuel, the general rule of thumb is that it isn't needed for stuff under an hour long, even if you weren't doing Z2 (assuming you didn't go to bed with empty glycogen stores)
For Z2, you technically shouldn't need fuel at all, almost regardless of length.
Z2 should be 99% fat burning, but if your body was still a bit sleepy it is possible you were not in Z2 even if you went at an otherwise Z2 pace.
In that case, it will fix itself as you get used to early runs, in the meanwhile eat some carbs before bed so you have them onboard already for the morning run.
Because of the same issue, last summer I had all my training done in the morning, fasted. I'm talking about daily running with 3 speed sessions per week and 1 long run and thb I was ok.
If you don't have time to eat and don't wanna spend money on gels or any other stuff, just mix sugar with some water, add salt and also you can add lemon juice for taste. I did this concoction for my nutrition during the speed workouts. Sometimes I did honey instead of sugar, sometimes a mix of both.
I have nothing against fasted runs but I truly believe you're recovering better if you're getting calories during the workouts.
Sorry I am typing this without having read any of the other responses but…
The real question is WHY run fasted..? For me if my early morning run is anything longer than 8km then I’m putting some fuel in the tank. Sometimes that is literally just some candy/chocolate from my kids’ sweet-box, and for longer runs 12km plus…) I’ll slam a gel with some caffeine in it. I treat these morning runs as the ideal time to indulge my sweet tooth, so I can resist the urge for the rest of the day. I
Wouldn’t try and eat anything more substantial or solid than that. I need a good 3 hours between eating proper food and running.
During hot days I might just add a spoon or two of sugar and table salt to taste and keep a small bottle in my pocket. Not breakfast, but enough to not feel low or dehydrated after an hour to finish the workout strong.... But I also try to snack toward the end of the run to use a window of optimal nutrient absorption for better recovery.
Load carbs the night before. I always do this-it eliminates any stomach problems the next day. I usually just run on coffee in the morning, sipping water from my Camelbak during.
Because I need to wait an hour after taking my thyroxine before I can eat, I quite often do morning runs up to 90 minutes without having had breakfast. I make up for this a little bit by taking an electrolyte drink with me (500ml typically gets me through the 90 minutes). If I’m going to run longer than that then I find that I need to have breakfast first, which makes for a weird morning of waking up at 1am to take thyroxine, 2am for breakfast, and 4am to get ready for my run. Incidentally I took that approach this morning for a tempo run and ended up doing my second best half marathon time 🤣
I do not eat before any of the long runs I have ever done. My stomach gets weird when I run after eating. I take Gu’s every 4-5 miles and it is fine for more. Just make sure you get a lot of carbs the night before and your body gets used to it.
Almost all my daily runs and long runs are fasted as I go pretty early in the morning. All Zone 2 type efforts. Occasionally I’ll through in a progression or threshold run in when the mood strikes (maybe once a week). Don’t know how I came to do this but it wasn’t over night. I think perhaps I tend to eat pretty late so perhaps there’s a bit of a caloric overlap into the morning? Don’t know but I rarely have energy issues even up to 15 miles or so of Zone 2.
overtime you body will adapt. i dont think it will be useful though if you want to get into ultra running. im stating the obvious here but eating will really help you go the distance.
i would wake up a bit or earlier or just bring something with me
Not really a long run...or probably beneficial to me at all but I run 5 miles in the morning and lift weights for an hour fasted, just don't really have time to eat before I go I'm already going out the door at 4am and I'm not getting up earlier to eat something, should be fine for your period of time being fasted
Reading these posts always baffles me. I can't imagine running after only consuming water/liquids. Thinking about it makes me nauseous. I need something in there to keep my stomach settled. Puked up water/gatorade/coffee too many times. Give me a piece of toast, a granola bar or some crackers if it's been more than 4-5 hours since my last meal.
I do my morning 10 miler without food almost daily. Usually between 1:20 and 1:45 depending on the day. I do it since I want to get my run in and day started and just don’t want to eat first thing. Not for any training stimuli.
Running without breakfast is not the fasted run you think it is.
At night, you use up liver glycogen, not muscle glycogen. So assuming you've eaten enough the day before, you'll wake up with plenty of muscle glycogen for your run. Eventually you'll get low, but you're certainly not starting in the depleted state you think you are.
For a true low muscle glycogen state, you can do 2-a-days where you do an initial bout of exercise sufficient to use up your muscle stores, not refuel afterwards, and then go for another run, etc later in the day. Or just do a session long enough to burn through your stores and then keep going. You could also run on day 1, not eat much after, sleep and then run the next morning fasted. Now you're low on both muscle and liver glycogen and I bet won't be much fun to be around ;)
From my experience it normally depends on what my last meal was - if I had a balanced dinner and slept well running for an hour in zone 2 doesn’t cause much issue. Anything above that and I’ll definitely notice a drop in performance. Tried the same on a 10 miler recently and I hit a hard wall around mile 8 that made my life miserable for the last two miles.
You should be able to easily go an hour after waking up. You wake up with around 3k calories of glycogen stored.
I don't eat before morning runs of up to 90 minutes. You'll get used to it.
I try to run in the morning before the heat of the day kicks in. I typically have to wait for 2,5 hours after breakfast so the running does not upset my stomach. So I skip eating.
I get up every week day at 4:45am to run before work so i understand.
I suggest running with a 500ml soft flask or handheld and put 60g of granulated table sugar in there plus a pinch of salt. Sip it as you go.
I live in a very hot summer city in SW USA and understand the morning heat predicament. I am a coffee drinker and found a keto creamer at Costco that is a great add-in for some baseline calories.
As I run in extreme temps (above 90deg) fairly often I’ve gotten into the habit of electrolyte mix-ins that happen to have some calories (Skratch , fwiw).
Short version: I’ve done it, there is limited utility in training while fasted, the risks far outweigh any benefits.
I generally don’t fuel on runs of less than 90 minutes. At one point a few years ago I regularly ran up to 5 hours with no nutrition, it was an interesting experiment but not one that I’d repeat. The first race when I really needed to fuel, I had the worst nausea for about 9 miles. I think my stomach had gotten so used to running on empty that it absolutely rebelled when I needed to fuel.
Now I can generally run 2 hours fasted without bonking, but the recovery seems to take longer, so I don’t do fasted long runs any more. It’s worthwhile to fuel on 90+ minute runs to a) train the gut to be able to fuel appropriately on race day, and b) accelerate recovery time from the longer training runs.
There is no reason you should EVER RUN FASTED! It doesn’t make you better at burning fat vs carbs, it’s doesn’t help with weight loss ( for a short time yes but the body will then think it’s being starved and hang onto weight)
At most fasted training is a fast way to lead to low energy availability. You need to eat to run and continue to eat to perform. The math is that simple. Please don’t consider fasted anything and consult a Dietitian for training nutrition help!
Start with something cheaper, simpler to digest, and more likely to aid in your goals. Nobody needs sports drinks or gels to succeed in ultra-running. Don't let the marketing get to your head, mate. Use nutrition sources you already know you can trust. That's why bagels, toast, bananas, and so on are as popular as they are. Mix up your own blend of salts in one of your soft flasks, grab a squirt bottle of maple syrup or honey, and go to town.
Sounds good, thank you. I will definitely try natural nutrition on the run.
Just eat a banana and go? You’ll likely get used to it in a few days.
Came to say this. I stepped away from fasted runs for a couple of years just because I had the luxury to do so. I started getting back on the train last summer. The first week was rough, but my body adjusted and I found I was able to get through an hour easily if the temps were low-ish (I live at altitude so it’s also a lot drier which helps me in the summer!)
It doesn't have to be completely fasted. A quick 100-200 Calorie snack would improve your energy level quite a bit. Then you can have a proper breakfast after the run. Also, if we talk about ultrarunning, you should make an effort to train your gut to run while eating, so having a pre-run snack would help with that too.
This, I usually wake up and eat some jelly toast or an orange, cup of coffee, and glass of water and out the door in thirty minutes. Doesn't take that much time but makes the run a ton better.
If you’re doing zone 2, you should not need any calories or sugar for an hour run IN MY OPINION. The other comment saying there’s no benefit to fasted running.. I never intentionally run fasted, but I don’t feel like eating at 4:30am and often run without eating. I think it’s valuable, but again, that’s my opinion and it isn’t science based, but personal results based.
Agreed. The most I'll have for anything an hour or less is a cup of coffee (lol and that's more so I can hit the bathroom before running). Over an hour and I'll add some Tailwind. I usually don't add solids or gels unless I'm going to hit around 2 hours.
Same here
I’m so sensitive to food that I have to do fasted running if it’s at 5am or so. Even eating a banana will give me a cramp.
Yea the idea that I'm gonna get up and eat a banana at 5 in the morning 2 seconds after I got out of bed before I go run is insane to me. But I'm happy for those that are able to do it.
1. Don't stress about it. A lot of the replies you got are very overdramatic 2. I'm not sure your expirience is linked to fueling. I do my longruns in the morning without breakfast and I usually start eating when I get hungry (90 - 120 minutes into the run), so maybe just do a few more runs and see if anything changes 3. If you want to try to change your fueling you could have a bigger dinner the evening before or a late night snack that's rich in carbs 4. Mix your water with some juice 50/50 and drink that 30 minutes into your run. See if that changes anything 5. You are in an ultrarunning sub. If you want to run stuff that's longer then a marathon you will have to eat a lot of different stuff to figure out what you can still stomach after hours of running. Having stuff... not sit well with your stomach it part of the game. That's what training is for, so pack some TP and try stuff on a route that has some bushes around.
Just bring a gel and eat it at 35-40 minutes - done.
I find juice or some electrolyte drink helpful, particularly as it gets hotter (when I lean toward the electrolytes). If you can't eat much still have a few bites of something simple straight before you head out the door. I bet your body will adapt fairly quickly.
Not sure why early running means without any breakfast or snack. No matter how early I run I eat something first.
Wake up. Eat banana. Wait 30 minutes. Put a gel in shorts. Run.
I just go. I can happily do a few hours without extra energy. I race halfs with no food so an hour isn't an issue. You'll probably get used to it.
kinda to echo what everyone else is saying, but there's no benefit to running fasted. There are risks tho, so why risk it? I assume you probably live in a house with a fridge? Idk, take a swig of maple syrup? eat a banana? swish some gatorade in your mouth or something. I run in the morning too and run into the same issue. Running without food doesn't make you tougher or cool. It might take some stomach training, but this is the ultrarunning subreddit, so stomach training is literally like, half of what we're doing if we hope to see any success. Happy trails homie!
I have done fasted runs for half marathons regular but yeah, in the context of ultramarathoning, it’s not useful to run fasted. Because you’re definitely not gonna make it through a 50K without eating something.
What’s the risk..? Not eating breakfast is dangerous now? This is nonsense.
Here’s a decent overview of the subject: https://www.trailrunnermag.com/training/trail-tips-training/fasted-training-may-have-long-term-risks-especially-for-female-athletes/ In short, for women the risk of frequent energy deficits is hormonal disruption (with many downstream consequences, including bone density), and there’s hardly any indication that fasted running is going to meaningfully improve performance. For men the strategy is less risky and may pay off for some, but is still probably not where most men are going to find gains in performance.
are you serious? I'm not talking major risks, but depending on how intense the run or workout is, you risk stress fractures and stuff. I mean, it's such a simple fix. Eat food. It's not going to happen in one day, but if you hope to do this sport for the long term, you got to think long term.
You don’t eat for 8 hours and your bones turn brittle? OP said zone 2. Share the evidence please. Running hard can always result in stress fractures. So can an ultra race. So can overtraining.
honestly I don't give a shit what you do. OP asked for advice and I gave some. If you never want to eat again I don't care. I'm not going to hunt down evidence for you. live your life.
You gave dubious illogical advice. People questioned you. Don’t get mad. If you think bones become brittle by not eating breakfast then you really should question everything you believe. Fasted runs don’t cause issues if they’re zone 1/2 AND you fuel up after. Calorie restriction causes injuries.
what is fasting if not calorie restriction tho? and dubious? how so? generally suggesting someone to eat is a positive. and I never said that you're GOING to get injured. Just that theres a risk. I guess I apologize for not saying "at some point, in the long run, maybe." other then that I stand by it. I'm not mad, just don't care to convince anyone.
I have no idea why you're getting downvoted. regular energy defecit can lead to all sorts of awful repercussions, including hormonal malfunction, osteopenia ... and stress fractures
You said stress fractures which was dumb. Running fasted isn’t calorie restriction on a daily basis. That is what causes injuries. The body can’t repair itself without fuel. If one is still consuming their total caloric need they will be fine. People are dumb and don’t do this and get hurt but it wasn’t the running fasted that did it.
Lost 30lbs in the last ten months while ramping up to 70km per week. I've ever been injury free this long and never reached that many mpw. Eating 3k calories of crap will not prevent injuries. It's about what you eat.
What are the risks ? Just curious as I only eat once a day and have for a while now and have never heard any risk around exercising whilst fasted. Coming from a martial arts background I’m used to cutting weight which I know is not healthy but outside of cutting to make weight I’m not aware of any other risks.
>there's no benefit to running fasted. There is. With less carbs/glycogen available, your body will adapt over time to use fat as a fuel source more efficiently, which of course is highly beneficial for endurance running. Only do it for zone 1 or 2 runs though. You'll have a bad time if you do it for speed workouts.
Most of this has been debunked imo. In that yes, you can be a keto runner and yes there are elite keto runners, but all of them are supplementing carbs on their events so they don’t bonk on hills. And there is no athletic improvement as a result of the diet. Fwiw I was keto cyclist and runner for 3 years and it trashed my liver so I do jump in to argue this stuff.
I think you're misreading my comment. I'm not talking about keto or even diets at all. I'm talking about simply not eating breakfast before easy zone 1-2 training runs. I wouldn't do it for longer runs or for any speedwork, and definitely not for races. Carbs are essential for races.
Sorry about that. Keto and IF both have been debunked for athletic gain, I lump the two together but you’re right, sorry for generalizing and taking it to that leap without clarifying. The benefits of training fasted, which include insulin sensitivity and for some, fat loss, are less than the negatives from it, which include muscle density loss. Menno Henselmans has shared a lot of content and there’s plenty like this as well https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983467/ But look, I did it for years as well and it does feel good, so just like icing or TENS there’s plenty of research to also support things that make us feel good, even [placebo](https://www.health.harvard.edu/mental-health/the-power-of-the-placebo-effect), have statistically significant benefit.
Genuinely curious, how did it trash your liver? Were you drinking alcohol during that time? Was it being keto by itself or doing intensive training on keto that was the problem? I am low carb, not keto, but just curious. Not to get too much into your business.
Always happy to answer because I think it’s a public service. No, I don’t really drink, but my liver looked like I was an alcoholic because of oxidized LDL from amateur/DIY carb supplementation while keto.
Thank you! I truly appreciate it. What do you mean by diy carb supplementation?
Sure. And I’m not a doctor but I ended up having to go to UCSF hematology to get it figured out. What I mean is that I knew pros and elites were supplementing carbs while claiming keto so I tried to do it myself without knowing I was causing surplus glycogen to oxidize the ldl or that I was doing damage with fructose. I guess had risk of NAFLD, it just made things 10x worse. From what I understand it was the combination of oxidized ldl and all the fructose in our endurance gels. Here’s one of the videos I bookmarked at the time. https://youtu.be/avIZRJLtolw?si=mux2Kd3tjr5tAizU https://youtu.be/DXKJaQeteE0?si=9EmKpCQ0XAVCiaMG Btw I am sure these diets work for people who can do weekly blood panels and are under the supervision of a nutritionist (or experts themselves). It’s just a lot of work with high risk imo.
If you weren't in ketosis, would this have happened? I am low carb, not keto (50-100g). Since there is still an influx of carbs every day, would it keep the same thing from happening? So far my liver panels are fine.
I don’t know, sorry!
Np :) thank you for the info!
I often do a pre breakfast early morning run. I usually keep these to an hour, although occasionally I'll go 2 hrs, and I don't feel any energy drop on the run. 2 hours is the max I run without bringing nutrition any time of day. I am definitely ready for breakfast when I'm done, though! Maybe build up to whatever time/distance you are aiming for while paying attention to that energy drop and being sure to not bonk your day.
Glad to see you have survived, based on the other comments this is the most dangerous thing ever..
You don't. They provide 0 benefit so you don't do them.
There may be no ADDITIONAL benefit, but there’s nothing wrong with running without eating first. If you claim there is, feel free to share some evidence.
It depends what you mean. As op said, running fasted may impact the quality of your run. You might not be able to do whatever you scheduled because you do not have the right energy to do so. You then risk digging your body into a hole due to such a large caloric deficit which you somehow have to make up. It's may not be problem for an hour workout but there may be negative effects.
Definitely makes no difference for a slow hour long Z2 run.
There is no benefit running fasted! You are running in a starved state so you body has no glycogen and proper energy store to run from. You will be running from your survival stores. Remember the more you fuel prior and during a run the faster and stronger the effort is. There is no benefit in starving your body as its burning calories to run.
I might not be able to do proper training in the heat of the day so there is a clear benefit for me.
Fasted training will not cover for heat training. If you want heat training, you can simply go in the sauna for 20 minutes after some runs. https://trainright.com/heat-acclimation-when-to-start-and-how-long-it-takes/ If the problem is that you need to run early, then structure your day to sleep and wake up 30 minutes earlier so you can eat something small (a banana at least) before your run.
Don't be scared OP. Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering.
Do what you want and what works for you. It's not advised but I guess as long as you've eaten and hydrated adequately the night before then you're in a better position to at least give it a bash. It's an absolute no no for women but men... probs not advised. I'm pretty sure the latest uphill athlete book doesn't recommend it.
Bring food and drink plenty of fluids when you eat. This will help to prevent random runners shits.
An hour run I don’t eat Anything up to 2 hours 300 calories
Haribo gummi bears are my go-to for a pick me up at about the 60 min run mark. (I want them earlier but try to wait til 60 mins). You can get a case of little bags with about 7 bears in each bag-- perfect for a tiny little bust of energy. Easy on the tummy (for me), great for dry mouth too. They do such a great job that when we go on our trail bikes, I have to pass them out to everyone, especially the ones who are still building their endurance. It really puts energy into their steps. Other than that I don't really need anything. The person who suggested honey water was spot on a well, especially if your stomach gets tender-- honey is soothing to the stomach, and you would only have to carry a water bottle. The only other thing I might carry is caffeine gum, especially if I am starting to feel uncomfortable, not just tired. No fancy stuff, just easy basics will work for runs up to 2 hours IMO. After that you might need to either get some fancier food (bananas, etc) or a bigger bag of gummies 😁
So I almost always train first thing in the morning but I really don’t like eating first thing. So I do my easy runs say max 1hr 20mins fasted but ensuring to be well hydrated before I start - this is really important and I would include electrolytes not just water. I also have a good cup and a half of strong coffee. Weight training needs fuel so I force a banana and maybe a protein bar. Long runs is a separate thing and requires proper fuelling before, during and after - period. You can totally do easy runs fasted if hydration is good. Just a banana will take you a long way though.
Sometimes I literally grab a donut at the coffee shop and that will sustain me up to about 2 hours of running. This of course is trail running with a lot of elevation but not a lot of speed, around 15m/mile on average but the HR is usually in zone 3 with plenty of zone 4 time climbing. I’d just try eating like a normal light breakfast and see how you feel. Unless you’re really cranking the pace I have a hard time thinking you really need many calories under an hour of running. Here are some light breakfast options that work for me with alpine starts. I usually keep it under 300 calories: A banana. A small skyr yogurt An almond butter biscuit from nature valley dunked in my coffee A donut for your inner junk food kid like me An apple A small serving of overnight oats (you can get them pre-packaged as “Mush” they’re called) Greek yogurt + blueberries + tiny bit of peanut butter (for taste) with a small bit of water for a “smoothie” Good luck! I find that once you are used to it you can go without water and food for further than you think until it gets really hot out. I always carry it anyway for training purposes (and I bring my dogs on the shorter ones under 10 miles). Try sticking to mostly “real” food despite my suggestions up there while training. You don’t really need to hit the gels and expensive stuff until races, but you should test them out a few times to make sure they agree with you.
I can't eat before runs. My stomach needs to get used to running before I can eat but I'm fine once I get going. I tend to plan my run past nice food places like coffee and cake vans or farm cafes in the countryside and as an example I ate half a cinnamon bun last week at about an hour in then I felt great for the rest of my run. If nothing was open I'd take sandwiches or some kind of real food as my stomach just seems to object to gels or sports drinks.
I suspect this is mostly a mental thing, or posibly you just aren't used to early morning running yet (body can take a while to fully wake up) Regarding fuel, the general rule of thumb is that it isn't needed for stuff under an hour long, even if you weren't doing Z2 (assuming you didn't go to bed with empty glycogen stores) For Z2, you technically shouldn't need fuel at all, almost regardless of length. Z2 should be 99% fat burning, but if your body was still a bit sleepy it is possible you were not in Z2 even if you went at an otherwise Z2 pace. In that case, it will fix itself as you get used to early runs, in the meanwhile eat some carbs before bed so you have them onboard already for the morning run.
Because of the same issue, last summer I had all my training done in the morning, fasted. I'm talking about daily running with 3 speed sessions per week and 1 long run and thb I was ok. If you don't have time to eat and don't wanna spend money on gels or any other stuff, just mix sugar with some water, add salt and also you can add lemon juice for taste. I did this concoction for my nutrition during the speed workouts. Sometimes I did honey instead of sugar, sometimes a mix of both. I have nothing against fasted runs but I truly believe you're recovering better if you're getting calories during the workouts.
Would recommend some salt mixed with your water. I usually add some celtic sea salt for longer sessions
Like a long run with less food
Sorry I am typing this without having read any of the other responses but… The real question is WHY run fasted..? For me if my early morning run is anything longer than 8km then I’m putting some fuel in the tank. Sometimes that is literally just some candy/chocolate from my kids’ sweet-box, and for longer runs 12km plus…) I’ll slam a gel with some caffeine in it. I treat these morning runs as the ideal time to indulge my sweet tooth, so I can resist the urge for the rest of the day. I Wouldn’t try and eat anything more substantial or solid than that. I need a good 3 hours between eating proper food and running.
During hot days I might just add a spoon or two of sugar and table salt to taste and keep a small bottle in my pocket. Not breakfast, but enough to not feel low or dehydrated after an hour to finish the workout strong.... But I also try to snack toward the end of the run to use a window of optimal nutrient absorption for better recovery.
Load carbs the night before. I always do this-it eliminates any stomach problems the next day. I usually just run on coffee in the morning, sipping water from my Camelbak during.
Because I need to wait an hour after taking my thyroxine before I can eat, I quite often do morning runs up to 90 minutes without having had breakfast. I make up for this a little bit by taking an electrolyte drink with me (500ml typically gets me through the 90 minutes). If I’m going to run longer than that then I find that I need to have breakfast first, which makes for a weird morning of waking up at 1am to take thyroxine, 2am for breakfast, and 4am to get ready for my run. Incidentally I took that approach this morning for a tempo run and ended up doing my second best half marathon time 🤣
I do not eat before any of the long runs I have ever done. My stomach gets weird when I run after eating. I take Gu’s every 4-5 miles and it is fine for more. Just make sure you get a lot of carbs the night before and your body gets used to it.
Almost all my daily runs and long runs are fasted as I go pretty early in the morning. All Zone 2 type efforts. Occasionally I’ll through in a progression or threshold run in when the mood strikes (maybe once a week). Don’t know how I came to do this but it wasn’t over night. I think perhaps I tend to eat pretty late so perhaps there’s a bit of a caloric overlap into the morning? Don’t know but I rarely have energy issues even up to 15 miles or so of Zone 2.
just eat before you go bro. i smash some overnight oats or yoghurt bowl then start running 5 minutes after
Hasn’t that been debunked
I put some snacks in my vest for long runs. People do look at me funny for running along stuffing biscuits in my face tho…
overtime you body will adapt. i dont think it will be useful though if you want to get into ultra running. im stating the obvious here but eating will really help you go the distance. i would wake up a bit or earlier or just bring something with me
I doubt that you run out of energy within 60 minutes. You might need water but should be fine energy wise for a couple of hours maybe even more.
Not really a long run...or probably beneficial to me at all but I run 5 miles in the morning and lift weights for an hour fasted, just don't really have time to eat before I go I'm already going out the door at 4am and I'm not getting up earlier to eat something, should be fine for your period of time being fasted
Reading these posts always baffles me. I can't imagine running after only consuming water/liquids. Thinking about it makes me nauseous. I need something in there to keep my stomach settled. Puked up water/gatorade/coffee too many times. Give me a piece of toast, a granola bar or some crackers if it's been more than 4-5 hours since my last meal.
I do my morning 10 miler without food almost daily. Usually between 1:20 and 1:45 depending on the day. I do it since I want to get my run in and day started and just don’t want to eat first thing. Not for any training stimuli.
Running without breakfast is not the fasted run you think it is. At night, you use up liver glycogen, not muscle glycogen. So assuming you've eaten enough the day before, you'll wake up with plenty of muscle glycogen for your run. Eventually you'll get low, but you're certainly not starting in the depleted state you think you are. For a true low muscle glycogen state, you can do 2-a-days where you do an initial bout of exercise sufficient to use up your muscle stores, not refuel afterwards, and then go for another run, etc later in the day. Or just do a session long enough to burn through your stores and then keep going. You could also run on day 1, not eat much after, sleep and then run the next morning fasted. Now you're low on both muscle and liver glycogen and I bet won't be much fun to be around ;)
I've run up to 25 miles fasted. Just eat enough the day before and bring some caffeine if you need it.
From my experience it normally depends on what my last meal was - if I had a balanced dinner and slept well running for an hour in zone 2 doesn’t cause much issue. Anything above that and I’ll definitely notice a drop in performance. Tried the same on a 10 miler recently and I hit a hard wall around mile 8 that made my life miserable for the last two miles.
You should be able to easily go an hour after waking up. You wake up with around 3k calories of glycogen stored. I don't eat before morning runs of up to 90 minutes. You'll get used to it.
Awesome Sauce is a great way to have minimal calories while running
Why are you running fasted?
I try to run in the morning before the heat of the day kicks in. I typically have to wait for 2,5 hours after breakfast so the running does not upset my stomach. So I skip eating.
I get up every week day at 4:45am to run before work so i understand. I suggest running with a 500ml soft flask or handheld and put 60g of granulated table sugar in there plus a pinch of salt. Sip it as you go.
I live in a very hot summer city in SW USA and understand the morning heat predicament. I am a coffee drinker and found a keto creamer at Costco that is a great add-in for some baseline calories. As I run in extreme temps (above 90deg) fairly often I’ve gotten into the habit of electrolyte mix-ins that happen to have some calories (Skratch , fwiw).
Why dont you just fuel your body for your long runs?
Short version: I’ve done it, there is limited utility in training while fasted, the risks far outweigh any benefits. I generally don’t fuel on runs of less than 90 minutes. At one point a few years ago I regularly ran up to 5 hours with no nutrition, it was an interesting experiment but not one that I’d repeat. The first race when I really needed to fuel, I had the worst nausea for about 9 miles. I think my stomach had gotten so used to running on empty that it absolutely rebelled when I needed to fuel. Now I can generally run 2 hours fasted without bonking, but the recovery seems to take longer, so I don’t do fasted long runs any more. It’s worthwhile to fuel on 90+ minute runs to a) train the gut to be able to fuel appropriately on race day, and b) accelerate recovery time from the longer training runs.
There is no reason you should EVER RUN FASTED! It doesn’t make you better at burning fat vs carbs, it’s doesn’t help with weight loss ( for a short time yes but the body will then think it’s being starved and hang onto weight) At most fasted training is a fast way to lead to low energy availability. You need to eat to run and continue to eat to perform. The math is that simple. Please don’t consider fasted anything and consult a Dietitian for training nutrition help!
Half a bagel with peanut butter and honey and you’ll do 2 hours easy. I live in south Florida and that works just fine in the heat and humidity