Faster after fasting: is intermittent fasting beneficial for runners?

Intermittent fasting (IF) per definition means restricting whén you consume your food intake to a set number of hours, the so-called “eating window”. The most common way is to fast 16 hours and then eating your meals within the next eight hours. For instance, you take your first meal at noon, the last at 20h.

Over the last two years, medical doctors and fitness gurus worldwide spoke favourably about the new diet rage. Fasting would make you lose weight, help you sleep better, experience better fitness results, etcetera... 

On a science level, there was also some evidence in research in animals which showed that caloric restriction can have some important health benefits, and animals consuming fewer calories tended to live longer. 

That's said, but what we are eager to find out, is if IF is safe and/or beneficial for runners and recreational sporters in general. Can you combine IF with 5-8 hours of sports per week? Does it enhance your training? Should you adapt your training? 

Pro:

Along with driving weight loss, IF is said to stimulate the human growth hormone (HGH) production, to reduce cellular inflammation, and to prevents Type 2 Diabetes by decreasing blood sugar levels, and lowers bad cholesterol (LDL). All benefits simply specifying when you’re eating throughout the day...

Con: 

Given that pro-athletes require much more nutrition than recreational ones and must spread out these nutrients across the day when they have multiple daily sessions, this time-restricted approach seems to be a sub-optimal option. 

However, for recreational athletes who train for shorter durations and with less intensity—and therefore have lower energy demands—intermittent fasting may be appropriate, especially for weight management. There are some additional measures to be considered, though: 

- Adapt your training/meal timing: they should be synced properly. 
- Newbies to endurance athletics should workout fueled first before experimenting with fasted workouts

Conclusion: 

Start mildly and slowly, and give your body the time to adapt. Try fasting one day a week, instead of all at once. Start maybe with a 10/12hour fast, and work your way up. 

There’s no need to rush. You’ll find what works best for you over time. Most importantly, have fun and be safe. Talk to your doctor. Do your research.

Approach IF like you’d approach a new running program — with excitement and energy, but also appropriate degrees of caution and attention.