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As I understood it, carbs are turned into muscle glycogen but within 8-12hrs that glycogen is converted to fat stores.
I don't think so - your body wants to maintain a glycogen store. When you eat, insulin is produced which causes your cells to take up glucose and store as glycogen. If the glycogen stores are full then it becomes fat. If you don't eat more after your stores are full there won't be fat stored - I think.
Insulin also inhibits lipolysis/fat burning. So if you eat, insulin is released, but that insulin encourages you to burn glycogen which means your stores will be low which makes you hungrier and feeling worse after your ride. If you ride fasted, your insulin levels are low which means you burn more fat. And consequently get better at that. Just don't push it to hard, that will force glycogen to be burned anyway and you'll get really tired and feel like shit (I do).
If I have low glycogen then I can ride fine at lower intensities but hit a hard wall at a certain level, over which I can hardly go. The level at which this hits does seem to increase fairly quickly for me if I do it a lot.
I do my 15 mile commute like that. Strong coffee before I head out. It takes around 50 minutes to an hour, so doubt I see many benefits. Have tried to do more runs and rides without eating over the years - probably go up to about 2 hours before I start suffering.
It won’t work because he has no fat to lose!!
Sorry can’t find a link, but I remember reading an article about this somewhere, but basically:
Men - more fat burned when exercise is done on an empty stomach.
Women - the opposite.
Something to do with hormones released post workout.
Just chuck an emergency Banana in your backpack and give it a go for a week and see your results.
I’ve fasted/unfasted ridden for years tbh and I just generally find that most of my benefits are gained from not stuffing my face rather than the fasting YMMV.
Just watch out for underfuelling yourself if your doing hard for over 1.5 hrs as your likely to start to bonk and that’s interesting.(Easily recoverable with banana or yukkey gels just kept for emergency.)
My last unfasted ride actually ended up in a series of lemony snickets events with an ambulance ride and checkup in hospital.(black ice,no breakfast and out for too long in the cold -whilst helping to get a downed rider to hospital After coming off hard myself)
IHN & Pete - it was more wondering about energy systems.
Apart from the fact that if you near sprinted 8 miles it would only take 15-20 minutes
That's 24-32mph average - I can't do that!!!!!!!!!
No weighing scales in this house.
Lots of food for thought, I can see I'll get no energy system utilisation gains, but it may stop me having two breakfasts.
I did try it a while ago, it felt ok to do, I've lapsed back into eating at home again (a good precursor to my morning poo which I prefer to have at home #toomuchinfo). I might try it again next week.
The OP asked about the pros/cons of fasted training, they did not ask “is this the ONLY way to reduce body mass”
Ahh he didnt really mention the t word and tbh most normal people bang on about/associate fasting in the context of mass reduction.
The good thing about fasted training is that it’s free to experiment with which makes a refreshing change from people trying to flog you stuff.
(a good precursor to my morning poo which I prefer to have at home #toomuchinfo).
Which is sensible as you can shower so ensuring squeaky clean freshness 🙂
TBH have you tried the touching cotton training plan, guaranteed to increase your speed to work 🙂
That’s 24-32mph average
It sure is but that is the speed you would be doing if sprinting isn't it (hopefully higher)
Fasted cardio is a bit of a tightrope. Easy to try too hard and feel like crap/bonk.
But if you're just cruising along on a flat ride you'll be ok. Right up until you're not, then bonk.
I’ve played around a bit with some ‘depleted’ training (probably not truly ‘fasted’) and can’t say either way if it made any difference to my riding. I quite enjoyed making a strong coffee and getting out on the bike nice and early though.
I’ve been training like this since November. I’m on a high Protien / low carb diet, training lots of Z2 (slow, steady ish) albeit at the top of my zone within 90 minute to 3 hr sessions. If I do this in the morning I have 1 piece whole meal toast and 2 scrambled eggs after waking, if in the evening I’m strictly low carb - about 100g - all day.
Since November I’ve lost 10lbs and my power is up 6% measured by an hour effort. As Lunge stated, I also feel better riding with less food on board but it is essential I take fuel with me. Having said that the amount of effort I can do on my reserves and the amount of “base” as I have to support me seems to have soared.
I ride to work 5 days a week with out eating as it makes me feel sick if i do that and the fact that i would need to get up earlier in order to have the time to eat, i leave at 6am. I also find that i need to leave at least 2 hours or more since last eating before riding home to stop the sick feeling. This does mean that some days i end up riding home having not had any lunch. I’ve not noticed if it has any effect on my but i have been doing it in the morning for over 10 years now.
Been trying not to eat after 19:00 in the evening and skipping breakfast for about a year now. I haven't noticed any great problems on my commute.
I've tried mountain biking fasted as well and generally it's fine. The only time I find myself bonking is if I try to ride when I haven't eaten anything for roughly 4 to 12 hours.
If I've eaten within 4 hours I feel fine, if I haven't eaten anything for more than 12 hours I'm fine, it seems to be the 4 to 12 hour window that is problematic.
I’ve been training like this since November. I’m on a high Protien / low carb diet, training lots of Z2 (slow, steady ish) albeit at the top of my zone within 90 minute to 3 hr sessions. If I do this in the morning I have 1 piece whole meal toast and 2 scrambled eggs after waking,
You really haven't been doing the same thing at all. . Your meal is 250 calories. His coffee is c. 5 calories. You are how ever maintaining calorie deficit by another name.
I don’t think so – your body wants to maintain a glycogen store. When you eat, insulin is produced which causes your cells to take up glucose and store as glycogen. If the glycogen stores are full then it becomes fat. If you don’t eat more after your stores are full there won’t be fat stored – I think.
Probably something I misunderstood then. I seem to remember reading something about high levels of glycogen (pasta party) being useful as muscle glycogen for a period but then becoming/resulting in fat storage after that if unused but could well be wrong, or 'some bloke said on internet' stuff, like I posted.. Maybe something about liver vs muscle glycogen levels and rates that I got wrong end of. Whatever it was made me think about how much carbs I ate in relation to whether I was going to ride next day or not - but that's really just basic energy in vs out stuff.
So, any good links to 'the basics' on all this from someone with some authority? A few of us have half truths in mind as well as some experience from the riding, others may be posting from good medical knowledge? Interested.
Dr Shawn Beardens science of ultra podcast 69 has lots of info- from scientific papers rather than journalists.
I have been doing the odd "fasted" 10 mile commute in recent months.
TBF that's mainly due to wanting to save a bit of time setting off earlier than if I scoff something and not wanting to have stuff rolling about in my gut. I'm not tending to push very hard on the ride, just a comfortable pace.
But then I've been getting in, showering and starting work without much more than coffee till lunch time. This is only once or twice a week at most, but on those days I'm not totally famished come lunch time. Is that a "healthy" or terrible thing to do on occasion like that or should I really make an effort to fit breakfast in after a short "fasted ride"?
I seem to remember reading something about high levels of glycogen (pasta party) being useful as muscle glycogen for a period but then becoming/resulting in fat storage after that if unused
No this is true, I think. The carbs you digest end up as glucose in the blood, where it can't stay so your body produces insulin. This causes your cells to take up the glucose where it's either used (if you are exercising or growing) or stored (if their stores are depleted). If the stores are full then it gets converted to fat.
So if you've had a huge ride or lots of riding in the week your pasta party might replenish your glycogen stores, if you are about to set off on a big ride then as it digests it'll fuel your muscles (as long as you aren't riding to hard which diverts blood away from your digestive system) but otherwise it will just end up as fat.
lots of evidence pointing out that pasta party style thinking is a load of placebo an all .
^ Molgrips - so the 'glyc. stores to fat' isn't just a time thing, it's about use it or store it, overflows etc.
Dr Shawn Beardens science of ultra podcast 69
Will look it up, ta.
lots of evidence pointing out that pasta party style thinking is a load of placebo an all
As in, there's a limit to it's need/value, or on-ride fuelling can cover it?
It's not essential or all your fuelling, just about starting on full reserves (ime). Or in the case of old school XC events, something to line your stomach before drinking too much and racing badly the next day.
That it can be overdone. There is evidence to show glycogen stores can be manipulated (raised) with dietary carbohydrate levels in teh 24-48 hours pre-event and studies have also shown that higher glycogen stores benefit performance in both long and short events (even when complete glycogen depletion is not going to happen).
However, the best way to do this is to increase carbohydrates intakes over the 24-48 hours, not binge it all in one meal.
I thought this was a pretty good article about it:
https://road.cc/content/feature/239206-fasted-training-what-it-how-does-it-work-and-it-right-you
That’s 24-32mph average
It sure is but that is the speed you would be doing if sprinting isn’t it (hopefully higher)
Sure, but for 8 miles? Put it this way, the current cycling hour record is only 35mph and that's a professional athlete, on an indoor velodrome, using a track bike, with no hills, wind, or other crap to contend with!
Being optimistic is good, but this is STW and I suspect we don't have so many pro track cyclists on here 😉