I just started my 4th week on Keto.
I’ve been following a classic Keto meal plan very strictly and test my ketones twice a day, which have been consistently high.
But I’m having a hard time keeping up on my running. Before Keto, I was running 4 miles, 3 times a week. I was going to begin training for a half marathon this summer and possibly my first full this fall.
But after 3 weeks on Keto, my energy levels have plummeted. I have forced myself to do a run/walk 30 minutes a day/4 day’s a week. Even on days my energy starts to feel better, my legs won’t hold out. They start to turn to jelly by mile one and I can’t seem to even hit 2 miles. And then I bottom out again and it’s an effort just to get out of bed. Everything feels so heavy.
I’m supposed to do a 5k in just over a week. I used to win these races for my age group and now I have doubts I can finish one.
I’ve read everything about elecrolites, but I can’t seem to find what works for me.
I really want to keep up with Keto, but I also want to be able to run again. Seriously considering having a banana before my 5k, but don’t want to ruin all the hard work I’ve put into this diet.
Any ideas?
Running on Keto
4 weeks into Keto is not enough time for your body to learn to metabolize fats at the same efficiency as carbs. Basically youre throwing a new fuel source at it but it doesnt have enough of the fat processing machines to handle it and convert it into energy as it does with carbs.
Your workouts WILL suffer initially, probably the whole first month or more. It takes time for you body to build up the enzymes and other molecular mechanisms to utilize the new fuel source youre giving it. Which is why you feel like you stall out so quickly in your run.
Everything will work itself out but if your less than a month in, your body hasnt had the time to adjust yet.
Two options would be:
- Eat some carbs the day of your race then go back to a strict keto diet (realize that this will really set back your adjustement period)
- Or just keep calm and keto on! Accept that you might have to dial back your training for a few months and resume later.
My personal experience with running and keto was the same as yours. I could easily spend 40 minutes running straight before keto…but after I had to take breaks walking. Im almost 2 months in and Im feeling back to normal again. Im going to be training for a triathlon this summer and it will be my first real time doing it on keto!
Agreed, definitely too early to be keto adapted if you are new to keto, so your energy isn’t going to be there yet. I waited an entire year on keto before I went back to running, weight training and some pretty intense HIIT sessions. That was just me because my life was crazy plus I was losing weight rapidly without exercise. So I’m not saying it will take that long, but just by looking back, I know I wouldn’t have been able to do it at only 4 weeks, not even close.
Yeah, I know I’ve gotta stick with it. It’s just so discouraging to see such a backslide with my running. My sister just ran the Boston Marathon a few days ago and I can’t muster up 2 miles. 
At 4 weeks you are keto adapted, not fat adapted yet most likely but it probably has started since you are pretty fit. You are in the purgatory between if you do cardio exercises. Fat adaption does not come on like a light bulb but more like a slow boiling pot.
Some things though, if you were a heavy carb loader, you may be significantly damaged and this may take even longer to get to fat adaption, this is common in long distance runners who carb load from my understanding(its not my thing).
Another thing is you will need to work out in you LISS range, sprinting will just not work for you anymore you don’t have glycogen stores. This adaption once you figure it out will improve your times most likely. There are a number of runners here who can help under the exercise area.
I’ve never really carbo loaded, unless you count eating a banana before a run carbo loading. But my pre-Keto diet was heavy in carbs. I’ve done awesome staying away from them so far. I just feel weaker and weaker with each attempt at running.