General question about fuel

Just want to put this out there for people's thoughts and opinions.

Yesterday I did Parkrun (decent run, though it was quite warm - 29:27). No breakfast before going (I generally am better no eating before a morning run - around the 5k mark). The rest of the day I ate fairly lightly - a sandwich and half a scotch egg for lunch, and grilled cod on coconutty curried leeks with rice for dinner. I also had a protein supplement (worth 20g of protein).

This morning as part of a HM training plan, I did a long run - 80 minutes, 11.65km. No breakfast, no fuel on the run, no water (I carried a bottle on a slightly shorter run last Sunday, and it made my shoulders ache). I felt myself running low on energy at around 10k, and after the run and for most of the day, I've been feeling very tired, especially my legs. I can't remember the last time I felt so tired after a run.

I think I should have paid more attention to what I was eating yesterday, and possibly during the run. I wonder if I didn't properly refuel properly yesterday, and during the run today (which Garmin said cost me 1248 kcals) I didn't have enough energy readily available, and my body had to work much harder to find fuel for the run.

What do you think?

30 Replies

  • I don't claim to be an expert but I wouldn't run any distance on an empty stomach, let alone 11km. I always have breakfast before I go out (albeit just toast and coffee).

    I've learned from experience (see my thread earlier) the effect of drinking during a long run.

    FInally, I have to say that coconutty curried leeks sound great.

  • Hugh Fearnley-Whittingstall's "Light and Easy" book - it's lovely!

  • I don't know much about recommended amounts of protein, carbs etc. but I do know that I wouldn't have been able to run the longer run without something more. I would have had some porridge about an hour or so before and some jelly babies on route. I also take water on any run over 5k but I have a belt thingy with water bottles so I don't have to hold it x 😊

  • I haven't yet experienced water deprivation, but I think I should plan for it, so I'll have to get one of those belts!

  • As long as you are well hydrated before a run, then you should be able to run for an hour without taking on any fluids, dependant on temperature of course. Any run over an hour it is sensible to carry water. Bottle belts get my vote, rather than carrying a bottle in your hand which imbalances your arm action (unless you have one in each hand!!)

    I normally have half a banana and about 400ml of very dilute grape juice immediately before going out of the door for a 5k run. Up that to at least a full banana and 500ml before a 10k. Longer runs require fuelling en route. I reckon that I need to take something on board after about 45mins and then every 30 mins after that. What you eat is up to you. I have never tried gels and don't really wish to, but did experiment with a NAKD berry bar last week and that served its purpose and was easy to manage while running, although they will stick your mouth together and require a water supply.

    Because of the later start of parkrun, I normally have a small bowl of fruit and muesli and a cup of coffee beforehand, which seems to work pretty well, although I generally prefer to run on an almost empty stomach.

    Refuelling for longer runs is something worth experimenting with because it helps you avoid that heavy legged slog to the end of your run. It is worth making sure that you take on carbs and proteins after a long run too, even if, like me, your desire to eat is suppressed. Scrambled eggs and baked beans on toast smothered with cheese hits the mark for me, having refined taste.

  • Thanks for that - it's really quite a complicated thing, isn't it?

  • I don't think it is really complicated, Steve, but it is certainly worth doing some research and personal experimentation to find out what works for you.

    You can't run and your body does not recover, without fuel and hydration. Running teaches you so much about body and mind and how to get the most out of it. I know I didn't expect any of this stuff when I started C25k!!

  • Yes, I agree. I think the science of it is fascinating. I realised a few weeks ago that with increasing miles a week, I needed to pay attention to taking enough calories in, or I'd keep losing weight. Getting the protein in is important too.

  • I don't run in the mornings, I run after work so I'm already fuelled from breakfast, lunch and a mid afternoon snack. However the times I have run in the morning I've always had breakfast first (personal preference). I agree with Iannoda, anything about and hour/10k and you don't need to worry about water etc but anything longer and you can start to feel the energy dipping and at that point trying fuelling/water strategies is a good idea. Good luck trying stuff out!

  • Thanks, LF!

  • I think your body is telling you it needs more fuel. This interests me a lot as I have a high metabolism and even before running I needed food regularly (every two hours) but now with the running I have to be careful and eat properly otherwise I'm ravenous all the time and not eating enough/ the right things really affects my runs.

    If I run in the morning even for short distances I eat porridge with honey. If I'm running a 10K then I add toast with peanut butter. Immediately after a run I drink my own chocolate milk with whey powder, for added protein and it fills me up. Then the rest of the day it's normal - lots of protein, veg, etc. and water.

    I did see an article recently which gave a table for working out how much extra calories we need for running and I'll dig it out and post it as it was useful.

  • Apart from lack of fuel, could it be a symptom of overtraining?

  • No no no no !!!!!!!

  • I found fuel one of the hardest things training for my HM. I have a slower pace so I am actually out for longer and needed to make sure I had fuelled the night before my longer runs. I ended up using myfitnesspal for the breakdown of carbs, protein and fats. I found that I needed slightly higher carbs than I was eating to cope with the runs so the night before I aimed at having 60% carbs the day before a long run.

  • You could try taking some diluted sports drink on the next long run, and have a few sips 20 minutes before you think you'll start to tire. It will rehydrate you and give you some sugars to pep you up. I take that on any run longer than 10k, and that's in addition to breakfast, etc.

  • I'm finding this threat interesting. I struggle when I run as I almost immediately feel thirsty, (doesn't matter how far) the most I've ran is 4 miles and when I've gone 3/4 's of the way my legs feel heavy and tired. Could the instant thirst etc be due to dehydration and lack of calories.

  • I have read that there is a 1-hour window during which your muscles are particularly able to re-fuel after a run. I think that's primarily for runs of an hour or more but it might also be a good plan for a shorter run before breakfast. If you don't take on some carb's during that 1-hour then it can take longer for your muscles to rebuild their energy stores. If you have a rest day or two then that gives your muscles the time they need to recover. If not then you might notice the deficit.

    You store sugars in your muscles as glycogen and, when you run, that glycogen gets used up. Running before breakfast is particularly effective in using up stores because you don't have any food in your system. That means that your parkrun may have depleted your muscle glycogen. If you then didn't have any carbohydrate in the 1-hour window after that run, you probably wouldn't notice except if you try to run next day. Run again before breakfast, however, and you are relying on stores that didn't get topped up fully after last time.

    Apparently a pint (500ml) of sweetened chocolate milk, or similar, has around the correct amount of carbs and protein for a post-run refueling. If you are running again the next day then you might like to consider trying it.

    I usually run around an hour without taking water unless it's quite hot (for the UK). 1.5 hours/10 miles or more and I will generally take a belt with a couple of 200ml bottles. Yesterday, in the sun, I needed the 500ml I carried and was forced to stop at a co-op I was passing and buy another 500ml only a mile from home because I really thought I might end up in trouble if I didn't. The belt is much better than carrying. I got mine cheap off Sports-Direct.


  • That kind of supports my own thoughts. Thanks. It wasn't a good feeling!

  • I think you are spot on with your last paragraph.

    My morning runs are done on previous day's fuelling and rest of the day replacing used energy I.e. no breakfast just unsweetened tea for up to 15k. Weekday runs are in the evening so fuelled by the day's meals and then dinner. Still playing with what to eat on a long run, although liquid is only ever water, I have a bottle belt.

    In the end it's like most things - whatever suits you and your digestion. Good luck with your training.

  • As on clue, I read this today!

    Since last week I decided to keep a diary of what I eat the day before a run to see how it affects it - for the moment I found best pre-run dinner forme is fish, spuds or rice and vegs

  • But why so many people drink so little ?

    I have about 1 lt before I run, a bottle of 500 ml during the run, (if no more than 1 hour, if longer is the 2 lt hydration pack) and another litre when I finish, and that is on anything longer than 30 minutes (I gave a recipe of my homemade sport drink in reply to Acton earlier)

  • I don't seem to have a problem with hydration, strangely. I've got in the habit of taking a pint of water to bed and drinking it overnight. Seems to work ok.

  • I'd say you'd not eaten enough. 10k is too far to run on empty. I've done it thinking I was doing a 5k so didn't bother. I totally had nothing left and I knew it was lack of food. It's like your car running out of gas. You feel awful don't you. As if your legs have nothing in them to propel you any further. You could kick yourself as it seems a waste of a run

    As a matter of interest why the protein supplement? You could eat real protein and forego a supplement . Supplements don't replace real food, or shouldn't

  • I've been following, and it tells me I need to be eating more protein than I'm getting through a decent diet. Also, it seems that the window for getting the protein in you after a run is fairly short, so using a supplement can be effective.

    After long runs I do tend to use a recipe from RW - a "Monster Shake" - 35g oats, 50g nesquick, a banana and a pint of full fat milk. Tastes ok and is fast to take on board.

  • ....and how I felt? Well, I was definitely running out of gas from about 10k. But it was after the run that I felt really awful. My legs were shot, really tired. I need to think much more about what I'm doing, be more consistent about planning food consumption. 1250 calories is a lot to have available for a run.

  • I have actually switched my longer runs to Mondays to combat this issue - I found weekend mid mornings I was running out of gas after about 5 miles. I can't really face breakfast most morning so usually only went out on a cup of coffee. No wonder I felt crap!

    I now so the longer run after work when I have fuelled up properly during the day. This might be a problem when the runs get over 2 hours but hey, not training for a madathon just yet ;)

    re water on the run, not needed it just yet and I am up to 80 mins running like yours. I used the shot blok jellies instead which helped the juices flow and keep the engine running. Going to invest in a water belt this week as it might be an issue when going above 90 mins

  • I always eat about an hour before my 10k runs. I never used to until I passed out and spent three hours in hospital. I had a massive bump on my head and a really lovely black eye. So I now have a couple of clementines an hour before I run and take water with me.

  • Sounds like you were running out of energy. Best bet is to experiment with what works for you - try to make notes of how long before a run you had your last meal.

    Also, you might want to have a quick energy boost just before you set off on your longer runs. It takes about an hour for the body to turn sugar into energy, so that means it'll be ready for when you need it.

    Hope you figure out what works, running on empty is a horrible feeling.

  • Interestingly, I was watching an old episode of some Police reality series yesterday morning, and one of the PC's was fasting for Ramadan. He set of in pursuit of a felon and found that very quickly he had to give up. Found himself in quite a bad way and put it down entirely to not being able to eat properly. Not the same as you I know, but evidence if it's needed that some fuel is always needed, especially for a longer run. (He only ran for about 1/2 a mile).

  • Interesting topic. My runs are very much like yours Steve. I never eat or drink before a parkrun which consists in total of 11k if you include my run to and from the park. I normally run very late on a sunday afternoon, again before i have eaten anything. I often have hunger pains prior to starting my run but they always subside once i start running. I normally run 10k but on occasions have run further up to HM. Sometimes i do feel very exhausted while other times i feel far better at the end of the run that at the beginning. I do agree with most of the posts that you should probably fuel up if running for more than 1 hour but you can overplay the science. Another day, another run and you could well be o.k.

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