As mentioned on the podcast thread I’m enjoying “Don’t tell Me The Score”. Yesterday I listened to the episode with Prof Satchin Panda where he talked about the Circadian Rythm. I wrongly - it turns out - thought this would be mostly about avoiding screens before bed. This is included but there’s so much more, mostly about fasting & when to eat which he makes a very compelling case for.

I know there are people on here who carry out fasting & I think I could adapt to eating over a 10 hour (09:00-19:00) window without too much trouble at the moment. There are times when I don’t think I could manage it.

  • Long run/bike rides when I think I need to have an early, decent breakfast.
  • When evening swimming resumes I need to have to take something on after.

How do you fasters cope with this, or do you feel that by being “good” 80% of the time you are still benefitting?

I’ve ordered the book as well & I’m trying to get the wifey on board.

I eat when I’m hungry, which means I have a 16 hour fast most days, it’s nothing about about being good or healthy, just eat when you’re hungry.

Obviously now you’ve listened to that you probably heard all about the hormone resistance that makes it hard, I also certainly wouldn’t pick any set hours, what if your hormones are different to the hours you choose? Maybe some “coach” could start selling kits to test it?

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In my very limited experience and opinion this works.

Four of five times a year I do a full set of night’s.

That’s a months work, 77 hours in a week, this gives me 4-5 one day weeks after it per set, I take the work day as my rest day and can live like a pro athlete without the money, sponsorship, results and Facebook likes.

During said twighlight shifts I don’t eat between 3 in the morning till 1600 hours when I wake.

I seem to actually gain fitness?! Diet is average to crap but I never gain any weight, not sure I could stretch the hours to 16 though…


Again, only personal experience.
I was injured last year so took 3 months off training. I looked for options on weight management as I eat a lot. I ended up fasting 8/16. Breakfast at 11am, last meal at 7pm. Same calories as before.
For me it worked. Felt great, lost weight ( 71kg to 66kg )and as above, seemed to gain aerobic fitness.
I do 12/12 now, and I’ve got no idea what the science says about this and whether it counts at all as fasting ( essentially it mean not eating before bed which I used to do )
As for fuelling long trading ride and runs, I always did my long run/ride fasted in any case. Between days shifts and night shifts, I’d go to bed 10 ish, sleep in till 12 next day, head out about 2, so that’s about 16 hours. Always felt better running after that “fast”.


I managed a 90 min run at a decent lick a few weeks ago that was fasted by accident almost.

I did feel very very hungry 20 mins after finishing, but went ok.

Not sure I could do a 4-5 hour ride though?

You mean you start depleted and eat during the ride? Unless your fat adapted ?

I’m constantly 70 kg now, my diet is not the best, how did going to 66 affect your performance?

I’m appreciating these insights & can imagine how difficult it must be for those of you working shifts.

@JibberJim the hormone resistance bit passed me by, I may have been drifting in & out of the podcast depending on my turbo efforts. Hopefully the book will enlighten me…or I could just listen to the podcast again :thinking:

I tend to do 14 hours a day - eat breakfast around 10 or 11 and stop eating early evening. I did a 3 hour Z2 Zwift session last week fasted without much difficulty, I wouldn’t feel so confident doing anything more intense.

I think the science says that eating breakfast and then stopping after lunch is good but it has to fit with your lifestyle and I would find that a chore. I generally feel better when I don’t eat early/late and that’s why I do it. Though if I wake up and want a fry up (like today), I’m going to do it.

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I felt faster at 66kg, especially running. Think it was worth about 15 seconds per km based on my aerobic training.
I’m not riding for 4 hours so can’t comment. If it’s steady miles I’d say try it, but anything above that you might need some fuel.
I’m always very hungry after fasted training. Usually eat about 1000 calories with 2 hours. :joy:


Don’t think I’d ever see below 69 but it’s food for thought, quite literally.

I’m tending to eat less on turbo these days, Tuesdays long effort had two cliff bars and two gels and felt fine.

I know some people fast, and that includes fluids … not sure that’s for us ?

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No. Not fasting fluids. That’s mental. I’m black coffee and water until breakfast.
On the 66kg, I am a small frame so that helps. 75kg is the heaviest I’ve ever been if that’s any kind of guide.


Two girls in work swear by this, they do 16 hours…?!

They certainly don’t eat in that time, I think they have fluids though, I’ve been very heavy body building in my late 30”s, 94 kg I think?

See how this year pans out.


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I naturally fast for at least 12 hours as I don’t really eat after 7pm. Fairly rare that I’d eat anything at 7 am either

Any rides or runs in the morning I wouldn’t bother with any food. I wouldn’t take a drinks bottle either for any shortish rides up to a couple of hours - I’m pretty ravenous from 9 am onwards though!

Like you @Doonhamer I’d definitely eat after an evening swim. Don’t know what it is about swimming but I’ve always got a huge appetite. Must be all the chlorine I’ve drunk

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I got into 16/8 for a few months at the beginning of the year . Found it fairly easy and would eat between 11-7. I was also doing all my runs early morning and would just have water/tea in the time I wasn’t eating. I even managed my long run 20-25 miles whilst fasting too, without any issues . I lost more body fat and felt much better for it . I’ll be starting again next week - I tend to do one month on another off just to mix things up .


Maybe it’s just conditioning but I hate not eating little and often
Bowl of cereal before bed at about 9pm
Hank Marvin on waking up - more cereal about 7am. Occasionally I wake up for another bowl of cereal in the night.
Then through the day longest I’ll go between snacks is 2-3 hours. Hungry now just thinking about it.
Couple of guys at work do the fasting thing, each to their own!
I’m 68kg / 180cm


Not sure we’re fasting fits in the really big weeks 16/20 hours, that will happen if there’s any races this year, which is looking more likely now.

I’m actually surprised how much of this goes on wether obviously planned or happening naturally like Adam.

Good debate for surec


I was having a filling recently (maybe that’s karma for all the grazing) and Dentist said he fasts all day Monday and Tuesday.

This was at about 5pm on a Tuesday & so I was slightly anxious. He did look a bit pale and shaky too :grinning:

  • the whole time he was talking to his nurse about Strava & of course I couldn’t get a word in because my gob was full of retactors ans stuff

I am more like @fruit_thief and tend to graze although I only have breakfast when I feel like it. I didn’t run until late last night, getting back about 21:30 so woke up hungry. Normally I don’t fancy breakfast until about 10:30, although I do have a small coffee with milk about 9. Fasting isn’t for me I don’t think.

ETA: I am actualy a bit overweight but that is down to chanign eating habits during lockdown (1 & 2) and exercising less due to covid restrictions and running injury. Since I have been back running this year and eating as I normally would pre-covid the weight is coming off.


I’m also a bit of an eater, starting at 07:00 & finishing around 21:30 normally. Also, like you I’m naturally about 180cm & mid 60kg so it’s not a weight concern.

My initial interest in the fasting would be to get a better sleep pattern, give my guts longer to repair & I recall something about joints becoming healthier.


I’m there in an hour!

First dentist for a long time due to covid, a steady hand is always good !

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My 4 year old does it naturally, even though we try to persuade her to eat breakfast, it’s often only a few mouthfuls.

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