When you think about your training programme, does it mandate pre-marathon carb loading, choosing menu items that are heavy on proteins and low on processed foods and sugars? That’s pretty typical. But have you ever considered what you can accomplish if you should decide to practice fasting while maintaining your normal activity levels?
In fact, fasting and running aren’t counterintuitive as proven by runners who either fast for health and dietary reasons or do so in observance of religious practices like Ramadan.
New research into the relationship between athletic performance and fasting is revealing; studies now show that, if done properly, fasting has the potential to improve performance.
How and why? Leave that up to us to explain it to you!
What is a fast?
The words “fast” and “fasting” are verbs and nouns, but the meaning is clear: A fast means abstaining from all food or eating only sparingly of some foods in accordance with religious practices included in the world’s three major religions: Judaism, Islam and Christianity. Fasting is mentioned in the Old Testament, the New Testament and the Quran as a way to atone, purify, show respect and discipline in accordance with one’s faith.
Over time, religious practitioners and the faithful have clung to this ageless practice, but an increase in holistic medical techniques in the past century has also made fasting a topic of interest to the scientific community for decidedly non-religious reasons: they want to know how fasting impacts health and performance.
How a fast affects the body
Surprisingly, a fast doesn’t chemically begin until the body is depleted of stored carbohydrates, a process that takes between 12 and 24 hours. Only when carbohydrate and then protein depletion sets in does starvation trigger a state of autolysis.
At this point, the liver converts fats into ketone bodies that race through the bloodstream. This state is called ketosis and begins a process of detoxification that is the reason some people fast in order to rid the body of environmental toxins during the ketosis state.
This is key: once energy is diverted from the digestive system, the body begins to heal itself as energy instead goes directly to the body’s immune system.
People on fasts repeatedly talk about the rejuvenating aspects of fasting and indeed, there are plenty of longitudinal studies published by medical authorities that point to fasters having longer life spans than non-fasters.
Two types of fasting
During Ramadan, the faithful do not eat or drink during daylight hours because they are honouring one of the five pillars of Islam. Observant Jews stop eating for 24-hours on the eve of Yom Kippur and, unless medically necessary to stay alive, neither water nor food may be ingested from sunrise to sundown.
Christians practice a type of fasting that’s much less restrictive during Lent: They eliminate one type of food or beverage from their diets throughout the Lenten season. There are also other religions that had incorporated some form of fasting practice into their doctrines.
It’s perhaps the trendiest style of fasting to come along in the last few years: specific periods of fasting as advocated by British doctor Michael Mosley and described in his book “The 5:2 Fast Diet”.
This fast is simple enough for anyone to understand and follow: one eats normally five days a week and fasts on the weekend. There are currently other scheduling versions that stipulate everything from fasting regularly during every 24-hour period to cutting back calories every other day.
Adopting an intermittent running/fasting lifestyle
Many runners have already begun to use alternative-day and intermittent fasting practices to improve their health, longevity and performance, but it’s important to pay attention to the way in which they balance fasting and running.
For example, some runners already adhere to an every-other-day run schedule and consume calories on those days only. Some runners prefer to digest carbs before and after a run to load and reload the system.
On non-run days, they may also adhere to Mosley’s recommended 500 calorie breakfast and lunch that are heavy on protein and fibre.
Another way to coordinate your intermittent fasting program is to work out less vigorously on the days you don’t eat or consume limited amounts of food.
Walk instead of run, undertake light Yoga or Tai Chi exercises in place of rigorous gym workouts or undertake household chores that require little exertion. Rev up your regular exercise practices on the days you eat.
If you not only want to coordinate your diet with your running but you want also to lose weight, doctors recommend focusing on proteins on the days you eat—-but schedule small, protein-loaded meals 3 or 4 hours apart.
Err on the side of caution
Your efforts to maintain a sensible balance between running and fasting can only be successful if you don’t lose sight of your body’s water intake. You already know how critical hydration is to a runner’s health and it’s even more important when you limit caloric intake. It’s not unusual for physical fitness professionals to recommend up to 13 glasses of water daily for those who practice calorie restriction.
It’s very important to recognize your limitations when you adopt any fasting plan. You may think, because you’re feeling energetic and enthusiastic as a result of your new lifestyle, that you can handle strength training activities at the gym, but save that energy for the days you consume the most number of calories.
If you experience symptoms that don’t feel right – excessive sweating, muscle control issues, severe fatigue, lightheadedness, dizziness, nausea, vomiting or trouble breathing – seek medical attention immediately.
Benefits of fasting and running
- When you fast, your empty stomach produces hormonal changes that actually build muscle tissue and burn fat.
- Insulin diverts sugars from the bloodstream to muscles, liver and fat cells where they’re stored for future energy needs.
- Beneficial growth hormones kick in while fasting to encourage new muscle tissue growth, improve bone quality and enhance the body’s physical functions. One study of men and women who went 24 hours without food increased the men’s growth hormone output by 2,000-percent and the women’s by 1,300-percent.
- Physical performance is enhanced because when calories are taken in, they are processed more efficiently by the body when it builds lean muscle mass. Athletes who train while fasting burn fat more intensely.
- Fasting runners have been shown to have improved VO2 Max readings that measure an athlete’s ability to take in and use oxygen more efficiently.
Does it take time for a body that has been well-fed repeatedly over a lifetime to adjust to a disruption that leads to a new pattern of eating?
Of course it does. But if you remember how it felt to begin your running program — the aches, pains, discomfort that plagues a body that isn’t used to regular conditioning — you know that you will eventually get past that discomfort.
On the other hand, there’s no need to be masochistic: if you try fasting and running and it’s not for you, your running buddies won’t have much patience if you turn into a martyr!
Have you ever been tempted to try fasting while maintaining your standard running routine? What were the results?