Do's and don'ts · August 2022 · 2 min read
We couldn't run past nine miles on keto
Three and a half years of keto, then a summer of long runs that fell apart at the same mile. What we changed, and how little it took.
For about three and a half years before the marathon we ate keto, and it worked for us. We'd lost weight on it, we felt good, and we had no plans to change it. Then in the summer of 2022 the training runs went past nine miles and started coming apart at about the same spot every time.
What it looked like
It wasn't dramatic, because the legs were fine and the lungs were fine, and then somewhere past nine miles there was just nothing left, the kind of empty where the pace goes away and doesn't come back. The first time we figured it was the heat, and the second and third times we figured it was us. By the fourth we noticed it was always the same mile.
What we changed
We put carbs back in, nothing crazy: more fruit, potatoes more often, rice occasionally, enough that the long runs had something to run on. The runs stopped coming apart and the mileage kept going up through the readiness series, and by October we ran a 30K on a plan that would have been impossible for us in June.
The other half of it was learning that once the runs get long you have to eat while you run, because nothing you eat before a two-hour run lasts the whole way. That sent us down the nutrition rabbit hole we're still in, testing what works in a pocket in Honolulu heat, and that's its own note.
What we'd say about it
We're not going to tell you what to eat. We don't know your body, your labs, or why you're on whatever you're on. What we can tell you is that the diet that made us healthy enough to start running wasn't the diet that could carry a marathon build, and the fix was smaller than we expected. Talk to your own doctor before you change anything, and then pay attention to the mile where your runs fall apart, because that mile is trying to tell you something.