Intermittent Fasting for CrossFitters

Nutrition is always a hot topic within the CrossFit community. Regardless of whether you are a veteran, competitive Crossfitter, or you have recently just started, you have probably come across the term ‘Intermittent Fasting’.

The Paleo and Zone diets have made a huge impact in CrossFit, but things are starting to move in a different direction. Intermittent Fasting has come to the forefront more recently for the numerous health benefits associated with this way of eating. Intermittent Fasting is now becoming increasingly popular among some mainstream CrossFitters and many casual gym-goers.

Like with any new fitness trend, there are still many questions to be answered:

  • Will it have a negative effect on my performance?
  • Do I have to give up breakfast?
  • Is it even healthy?

Let’s have a look at the basics, clear up any confusion, and find out if Intermittent Fasting is the right choice for you.



First of all, Intermittent Fasting (IF) is not a diet, rather it is a way of eating. It is a pattern that cycles between periods of fasting and periods of eating. IF does not detail which foods you should eat, but rather when you should eat.

Intermittent Fasting is pretty simple: Eat your meals within an eight-hour window during the day, and you are golden!

This puts you into what is known as a ‘fed state’ for eight hours, and a fasted state for sixteen.

For women, it is often advised to begin with ten hours in the ‘fed state’ and fourteen hours in the ‘fasted state’. Women tend to suffer a little more irritability and food cravings when they dive straight into the 16 hours of fasting, so it may be advised to work up to that, gradually shifting to a longer fasting state.

There are no set guidelines as to when to pick your eight-hour window, you have to do what works best for you. For best results, it is advised to be in the ‘fasted state’ during your training. You could start eating from midday until eight PM and train in the morning while in a fasted state.



Numerous studies have been carried out on Intermittent Fasting, in both animals and humans. These studies have presented powerful benefits for weight management as well as the health of both your body and brain, it has even been proven to help promote longevity.

When you sustain from eating for a set window of time every day, your body and brain both benefit. From an evolutionary perspective, it makes a lot of sense. For most of human history, we were not eating three full meals a day interspersed with snacks. Humankind evolved in situations where food was not always readily available, and we had to learn how to prosper when fasting. We no longer hunt for food, instead, we spend considerable amounts of time sedentary and we eat whenever we want.

Swapping to an IF diet extends your limits and enhances your performance in multiple ways. Here are some of the benefits: 

  • Encourages weight loss without having to restrict calories
  • Boosts energy
  • Supports cellular repair and autophagy (when your body uses up flawed tissue in order to produce new parts)
  • Lessens insulin resistance, lower blood sugar levels which can in turn help to shield off type 2 diabetes
  • Lessens ‘bad’ LDL cholesterol
  • Boost brain health by increasing brain hormones which may help the growth of new nerve cells and even protect from Alzheimer’s
  • Enriches memory and brain function
  • Makes cells more resilient
  • It is also much easier than following a strict diet

Intermittent fasting for crossfit


The brief answer: it might be.

The simplest way to get going (and in addition the way that will probably generate the most benefits) is by simply not eating your breakfast. Sounds a little crazy? Maybe even a bit intimidating!

For most of our lives, we have constantly been told that ‘breakfast is THE most important meal of the day’, so surely we shouldn’t skip it!! However, when we think about it, when we are inundated with work, or if we miss the alarm breakfast is often sacrificed.

Increasingly more people are making a habit out of missing breakfast. If you tend to do your workouts in the morning and avoid eating before training, IF could be a great choice for you. Read on to see how IF can work with your daily routine:


If you are up with the birds and have a limited amount of time before your day starts, and you have been trying to stomach a light ‘breakfast’ before you work out, we have some good news for you! Intermittent Fasting is most efficient if you don’t eat breakfast! Instead of having an energy gel or a banana have a big glass of water, a coffee or tea and 10g of BCAA or EAAs. As soon as you complete your workout, replenish yourself with another 10g of BCAAs or EAAs, you can repeat this again until your lunchtime window opens.


Lunchtime workouts are perfectly timed for IF Crossfitters. You get to break your fast with your largest, (and most deserved) meal of the day: Your post-training refuel!

Take some BCAAs before training and even after training with your lunchtime feast!


If you train in the evening there is a good chance that you will have already eaten a meal (or possibly even two) before you start. Depending on your program, and of course, your penchants, break your fast at around lunchtime (somewhere between 12-2) and if possible, plan for your largest meal post-workout.


Assuming you take them…..

On a rest day, stick to your typical window, but perhaps swap any extra protein in your first meal of the day for a slight decrease in carbs later on in the day. Maintain the same window as all other days.

Intermittent- Fasting and CrossFit How To Augment Your Results


There are always ways in which we can make our training and nutrition programs more efficient and effective. Reaching our desired goals for body composition, strength, etc. begins and finishes with what we eat. If you are not obtaining the necessary nutrients while in a fasted state, you will not be able to reach your true potential. Fasted CrossFit is a fantastic way to stimulate fat oxidation and lipolysis (where your body starts using fat for fuel). However, if you are not consuming the correct nutrients required to fuel your body, it will be harder to obtain your desired results.



The ultimate success of any weight loss or exercise regimen will depend on how safe it is to maintain over time. Here are some tips to keep you healthy and happy while fasting:

  • Organize your meals close to your moderate or high-intensity workout
  • Stay hydrated!
  • Keep your electrolytes up.
  • Keep the intensity and duration fairly low, to begin with, it can take some people a little bit of time to become comfortable with fasted workouts. Don’t overdo it.
  • Listen to your body!

Intermittent fasting for crossfiters supplements


If you are consuming fewer calories overall while fasting, chances are you are probably consuming fewer vitamins and nutrients. Whether or not that decrease is substantial enough to impact your health depends on many factors.

There is always the worry that supplements will break your fast. Most experts do not see that as a problem but having said that the timing of taking them is important.

To begin with, if you are only consuming water and/or black coffee or tea while fasting many vitamins could make you feel queasy on an empty stomach. If this is the case, you will want to wait until your eating window to take them.

Place an emphasis on reloading on electrolytes and maintain any vitamins or supplements that you already take if possible. Most importantly pay attention to how you are feeling, and when you do eat, be sure to eat a well-balanced diet.

Is intermittent fasting safe for everyone?


Hunger is the main side effect of Intermittent Fasting. Initially, you may also feel a bit weak and even perhaps a bit slow. This, however, might be only provisional, as it can take time for your body to adjust.

If you have any medical conditions, you should consult with a doctor before trying Intermittent Fasting.

Additionally, a program like IF can be extra challenging for certain people. If you are new to diet and exercise, have a particularly grueling job or very odd hours, or if you are a competitive athlete and train multiple times throughout the day, have stress or any sleep deficiencies can make IF very difficult. Be aware of all these factors when making any lifestyle choices and learn to listen to what your body is telling you.

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