Hi I started this diet on Monday 5th June and have lost 4lbs so far of the 18lbs I need to get into my healthy BMI, which is great and loving all the different foods that I love but have been banned on other weight loss plans. My problem is I’m training to run a Marathon in October. I’m struggling to run as my stable morning breakfast before a run was oats so simple. I’ve tried and failed 3 times to run my normal distances this week and my legs feel like lead. Anyone got any hints and tips for running and cutting out carbs.
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HiRunningban — once you become fat burning, you are going to have loads of reserve energy so continue to limit the carbs (as low as 20 grams) until you are burning fat —
My experience with lots of exercise (skiing/hiking) is that even when you are burning fat you may need additional calories and so EAT when you reach that super hungry point — but eat smart, mostly fat and protein with only a few carbs.
But I do need to add calories on days when I do hours of exercise — but it did not affect my reaching goal.
As Californiagirl says this way of eating means you get to run fat adapted (and there’s more fat to be used than the 90mins of glycogen generally stored by the body. I only run up to half marathon distance but I don’t carb load, and only drink water on longer runs, although if it’s hot I will add a bit of juice and salt as a home made electrolyte. My best body time for running is first thing so on those days I am running fasted too. When I get home I have kefir, about 200ml (with turmeric to reduce inflammation) and some cheese, usually a Babybel or two which gives me fat, protein and about 9gms of carbs. My not so best time is after work and they tend to be my shorter runs of 5-10k, followed by a ds spoon of peanut butter.
I think your run “fails” are just because you are new to this way of eating and once your body has adapted you should be fine. There are plenty of long distance athletes that do it fat adapted Google should give you some info.
Good luck with your marathon.
I’ve had exactly the same problem this morning as runningban. My normal morning run turned into a half run, half walk – I just had no energy. It was possibly my worst run ever – and I’ve been running for 30 years! I’m 5 days into the fast 800.
Anyone else had this issue with exercise on the programme? Does it pass?
Hi Jeremy, it can take several weeks to become fat adapted or keto adapted to the point where you can exercise with similar intensity to what you were doing on a carb based diet. I had some days in the beginning where even going up the stairs at work felt like I had done a really hard leg workout just beforehand. I think that was because of the glycogen depletion in my muscles. These days I exercise in the fasted state with no problems. As Californiagirl says above, be patient and listen to your body if you are getting quite hungry as you may need to add in a few more calories.
Today I had my next run and it went much better. I did have the same problems, but got 40 minutes in before I needed to start to walk and I did make it to 1hr 15mins in the end with some walking.
So still not right (I’d never walk normally), but hopefully it means my body is adjusting now.
A run yesterday — 40 minutes – not at my best, but fine. No need to stop running. Felt things were getting back to normal.
Today it was awful again. Run. Walk. Run, Walk. No energy. Absolutely exhausted. That’s 9 days in.
Joining this a bit late. I’m a keen endurance cyclist not runner but had similar experiences. My first advice is don’t rush it takes time.
My experience – I didn’t cycle for the first 2 weeks of 800 BSD I just didn’t feel like it. My first bike ride – a 1 hour try out felt like I had 40 miles in my legs before I started. I then just started to ease into the rides, once, twice three times a week and upping the time / distance. Within a few weeks after that first ride things started feeling more normal. I started the BSD at start of Jan. I can say probably the last 2 months I’m kind of back to where I was before. You’re body is adjusting to fuelling itself off fat, not carbs. It takes time! One thing I did when starting is keep the intensity on the bike low. Zone 2 heart rate, ie endurance or fat burning.
Don’t push it, listen to your body but don’t give up.
I still haven’t worked out how I’m going to fuel myself for long rides (3 hrs +) but that’s another discussion…
Thanks freester. It’s very useful to hear your experience – although a little frustrating to think it’ll take months to get back to normal!
Everyone(body) is different and you may not take too long for you(rs) to adapt. It will be easier if you fully commit to the way of eating. Your run on the 17th could just have been “one of those runs”. I no longer run due to injury but I did regularly run HM distances and further fasted, some of those runs were amazing, some were just runs and others were decidedly meh often no rhyme or reason as to why, so your bad run may have been just that, an off day for your body. Best wishes for the amazing runs to come.
Thanks Annie. That’s useful to hear.
I’m wondering whether having a sugary drink half an hour before my run might be possible – say 200 calories worth. If i had that, ran and burned off all that energy, would I then stay in ketosis? I can’t see why not as I would have already used all that energy up immediately, but I’m wondering if anyone has any knowledge on this.
I also found this on this very good page, which reassures me that the way I’ve been is the norm:
“Running Performance and The Ketogenic Diet
One of the concerns many runners have is that keto will negatively impact running performance.
And that’s understandable.
Carbs, after all, are a runner’s best ally. They’re the body’s preferred source of energy. I have stated that in the past and still believe so today.
But what if you want more?
What if you want to drop the carbohydrates and go full keto? Will doing so hurt your performance?
The answer is not black or white.
During the early stages of the keto diet, expect to experience drastic drops in performance.
Once your body has adapted to ketosis (and is using fat as its primary source of energy), your running performance should return to normal.
This, according to most experts, may take up around three to four weeks for your body to adapt to low-carb eating and using fat for fuel.
It took me about six weeks to be able to run normally on a keto diet. It will happen, but you need to stay consistent enough and play the long game.
Running Will Feel Like a Drag—And There is No Way Around it!
Running on keto will suck for the first few weeks. In fact, the first week on the diet will be a nightmare. You’ll feel exhausted every day from the lack of carbs, and the cravings will be, at times, too much to handle.
That’s a part of the process, and a sacrifice you’ll have to make if you’re serious about making it down the keto path.
Be patient. And do not let your ego stand in the way.
During the first few weeks, reduce your weekly mileage, go very slow, and walk, if you have to. Stick with the diet and keep working out.
During this whole time, consume more dietary fats, while keeping your protein intake moderate, drinking plenty of water, and replenishing your electrolytes.”
Jeremy, as the article you have just quoted says, and as I explained previously when you talked about keto flu, the key is to keep your electrolytes up. When you go keto as your body releases the stored water it has retained to use carbs as a fuel it also releases electrolytes. So you can get the signs of being low on electrolytes which is often described as keto flu. – You don’t need to use the fancy, expensive, electrolyte drinks just increase your salt intake.
JGwen – thanks for the tip on electrolytes. I do normally have an electrolyte drink before and after a run, but interestingly, didn’t on my bad run day so that could be it. I’ve done two rounds since which have both been better.
I made 1hr 5mins yesterday before hitting a wall. It was a painful run/walk for the rest of the way (40mins in total) – very hard work. I’ll keep the distances shorter this week.
Well. That phishing post has led me back to this thread so I thought I’d give an update on progress.
I’ve run 5 times this week, upping my distance compared with previous weeks to make up for the fact I’m doing 1150 cals a day not 800 (and that I only lost 2lbs last week!).
At the start of the week running continued to be an effort, but it was better than previous weeks. As the week has gone on it’s been better though, and I’ve just got back from a 1hr 10min run that felt much more like a normal pre-diet run. Not quite my normal ‘zip’ but still fine. I did have a higher calories day yesterday (still low carb) so perhaps that helped, or perhaps my body is just getting used to burning fat.
Anyway – things are improving which is the main message for anyone that finds this thread considering the impact on their own exercise.
Further update. A good week running-wise with no need to stop on runs to walk etc. However, the key lesson this week came this morning.
After a month on a low-carb diet, I ended that yesterday for a 2-week break. This morning’s run was a completely different world in terms of energy and speed. I felt bright and lively throughout and found the hills I’ve been struggling with in recent weeks were no problem at all. The same route that took me 37mins last week took 34mins today. No change in fitness – simply carb fueled!
In the long-term I don’t think I’m going to be able to keep up a low carb-diet for this reason, but I also appreciate the last month of slow, low-energy running has probably helped me to get rid of a lot of fat.
I think you need to look at the work of Stephen D. Phinney. Especially his book on the art and science of low carb living. – He is an expert on working with competitive cyclists and supports elite athletes with their diets.
It takes time for your body to adapt at a cellular level to using fat for fuel, each muscle cell will need to adapt. However, once you are adapted all the feeding routines needed to prevent “hitting the wall” because your body can only hold a limited supply of fuel in the form of carbs will not apply.
I can see that that would be useful for a competitive cyclist as they’re on 5-6 hour races each day when on a tour and learning to burn fat would be extremely useful.
I never run for more than 1.5 hours and so there’s no need for me to adapt in that way as my glycogen stores are sufficient to fuel me.
All I can say is that a month is not enough for full adaptation based on my experience today!