Intermittent Fasting and Exercise: The Facts

Diets, no one likes them. You dream of tasty food while chomping on celery as your daily snack. Perhaps that is why intermittent fasting is a popular lifestyle choice at the moment. That and the fact that it actually seems to work. Let's explore how to start intermittent fasting and, crucially, how to safely mix this in with exercise. 


What is intermittent fasting?


Intermittent fasting isn't classed as a diet but more as an eating pattern. You aren't restricted by the types of food you can eat, but you are limited by when you can eat. 


The most popular forms of intermittent fasting include:


  • The 5:2 fast - whereby you consume between 500-600 calories for two days each week (not in a row) and resume your usual eating pattern for the other five days.

  • The 16/8 fast - Only eating within eight hours. This includes skipping breakfast and fasting for 16 hours. This is the most popular form of fasting.

  • Eat-stop-eat fast - Perhaps the toughest form of fasting, where you don’t eat for 24 hours one-to-two times each week.


While you can eat whatever you like when not fasting, you still need to be disciplined enough and not overeat to see results. 


Remember that water doesn’t count when it comes to fasting. You should drink plenty of water throughout the day, particularly if you are exercising.


Does sleeping count as fasting?


You’re probably looking at those and thinking - I can’t not eat for that long! You’ll be happy to hear that the hours you spend sleeping DO count towards your fast. 


Who shouldn’t try intermittent fasting?


This type of lifestyle, while it has many benefits, is not for everybody. Some groups should not experiment with intermittent fasting; these include:


  • Women who are pregnant or lactating

  • Anyone diagnosed with an eating disorder

  • Individuals diagnosed with diabetes

  • People with low blood sugar issues


We always recommend speaking with your doctor before adopting any lifestyle changes. Your safety is, and always will be, our top priority.


What is the best time window for intermittent fasting?


The Harvard Medical School recommends fasting from 7am-3am or 10am-6pm, which seems to refer to the 16:8 fasting model. However, you will know your body the best and have a better idea of the ideal time-frame to fast.


Intermittent fasting and exercise


It’s an oldie but goodie to use this the following as your mantra for weight loss: calories in, calories out. Reducing your calorie intake while increasing your exercise to burn off calories is the simplest way to stay healthy, even if your goal isn’t about weight loss. So, it makes sense to exercise even when fasting. But it's essential to do this safely. 


How to intermittent fast and exercise 


As with everything fitness and lifestyle, it's important to remember that what works for someone else may not work for you. We are all beautifully unique, so you should find the best solution for your lifestyle and body. When merging exercise and fasting, consider the following:


  1. Do you find workouts easier on a full or empty stomach?

  2. Are you eating after your workout or fasting? - Consider what foods will be the most beneficial. For example, do you need a hit of protein to aid with muscle regeneration?

  3. What have you eaten? - if you have consumed a good amount of carbs, you should focus on strength training. Whereas if you haven't eaten many carbs, you will benefit from some form of cardio exercise

  4. Are you feeling dizzy during exercise? - if you are, stop. You can always try a workout later on or try activities with lower intensity.


Whether you are trying intermittent fasting for the first time or want to swap things up and try a different method, remember to speak with your doctor first and listen to your body.