Last time we heard from Xavi, he had just finished a marathon after three days of fasting.

In that experiment, he avoided cramps by taking in electrolytes in coconut water. But coconut water contains sugar as well, and he wondered if the glucose kept him going.

This time, he consumed only distilled water, while working and exercising. It was a disaster.

    It turned out to be an awful experience. Nothing went as planned. Hypothesis couldn’t be tested, and the fasting lasted only 6 days.

Fascinating to see how his body raised the alarm as the Brain Fuel gauge neared E.

    It is no secret that food gives us comfort, but in this experiment it became crystal clear to me. Most of the time I wouldn’t describe my feeling as being hungry, but my desire for food was immense. Sometimes so big I couldn’t think of anything else.

He lost four kilograms during the fast, then gained six after.


By no means a careful experiment, the difference between my 20k (12.4 miles) and half marathon (13.1 miles) was striking.

I ate two bananas before the 20k. I think the run started at 8 AM. I ate normally the day before. There were four aid stations, and I ate a Gu at the second and fourth stations. Around mile 10 I felt like crap and walked for a bit. I finished ok but really didn't feel great.

The half marathon started at 7:00. I got up around 4 AM and ate a Pro Bar Meal (390 calories), drank a bottle of Gatorade (160 calories) and had some instant coffee (150 calories). I took with me to the start a Stinger caramel wafer cookie (a knockoff stroopwafel and 160 calories) and ate it about 6:30. During the run I ate three Gus at miles 4, 6 and 9. I felt strong the entire run. At the end I felt like I could have kept going for another half. Three days after finishing I couldn't wait to do another and signed up for two more halfs and a full (November 2017).

Everyone is different and how we train and how our bodies react will vary significantly. But I'll definitely be eating a lot before my next half (August 20).

posted by wasoxygen: 966 days ago