Fasting

I just watched an excellent BBC documentary titled Eat, Fast, and Live Longer. Michael Mosley investigates the health impact of various forms of Intermittent Fasting including a prolonged 3.5 day fast, alternate day fasting, and 5/2 alternate day fasting.

The science is irrefutable - the health of this 55 year-old man was dramatically improved through short-term fasting. Lower blood glucose, lower IGF-1, lower body fat etc. This should significantly reduce his likelihood of developing cancer, heart disease and diabetes.

What effect does fasting have on endurance performance? All the conventional wisdom says that you need to eat at least once an hour during endurance training otherwise you’ll run out of energy and “bonk”.

This is certainly true for athletes who are unaccustomed to fasting. Their bodies are conditioned to use carbs for energy during exercise but the body can only store about 1,000 calories of carbs at any time. 1,000 calories is about an hour of running, so once depleted, these stores need to be replenished in order for the athlete to continue.

Fasting has been getting a lot of buzz in the fitness industry lately. It is great for fat loss and is associated with many health benefits including increased longevity and improved insulin sensitivity. However, it’s often met with derision by friends and family. Try explaining to a four-year-old why you’re not having breakfast.

I followed Martin Berkhan’s intermittent fasting protocol for about 9 months, with an 8-hour eating window between 12pm and 8pm. I did my workouts around 5.30am and took BCAAs until my first meal at 12pm.