Fasted Cardio When/Why?

Fasted Cardio When/Why?

Fasted Cardio When/Why (The Do’s & Don’ts)

Fasted cardio is a fat burning and weightless tool that has been used by many for years but what is it and why should you consider doing it?

Fasted cardio is exactly as it says, cardio that is performed while your body is in a fasted state.  But what constitutes being fasted?

This will be different for every individual and dependant on what meal you last ate as well as body type you have and what your digestion is like. 

When we eat a meal our body digests and breaks the food down.  The small intestine absorbs the nutrients into the blood where insulin delivers the nutrients to the cells.

How long this process lasts and how long insulin levels stay elevated is down to the type of food you eat and the size of the meal.  Once this process is finished your insulin levels go back to a baseline level and your body is in a fasted state. 

If you feel like your stomach is empty, that doesn’t necessarily mean you are fasted.  The state of absorption and high insulin levels post eating can last for 3-4 hours. 

So to get the maximum benefit of fasted cardio we would advise that you don’t eat for at least 4 hours pre-exercise and only consume water or black coffee in this window.

So why do fasted cardio?

Studies show that when you exercise in a fasted state there is an increase in lipolysis and fat oxidation rates.  In simple terms, lipolysis is the breaking down of fat cells for energy and fat oxidation is the burning of this energy by cells. 

Another reason to give fasted cardio a go is that your body primarily uses glycogen or stored carbohydrates to fuel exercise.  It's suggested that when your glycogen stores are depleted, which occurs after a fasted period, your body is forced to use other energy sources such as fat. 

So exercising in a fasted state could help you to burn more fat during your workout than when you are exercising non fasted. 

When choosing whether to do fasted cardio or not, lifestyle factors play a huge part in your deacon process.  For me, lifestyle factors such as time and when you eat your meals are the biggest reason you would choose to do fasted cardio and I regularly recommend it to my clients for its simplicity.

A lot of people believe they need to eat before a workout and again directly after a workout to get the gains and fuel the body needs.  But if you are trying to lose weight and struggle to reduce your calorie intake then fasted cardio can be really useful.

Its effectively like removing a meal or snack before you workout thus helping to reduce overall calorie intake in a day.  When you have a fasted period before you perform your cardio it can also help to keep you focused and stop you snacking and taking extra calories in where they may not be needed.  So great for helping you to manage intake. 

When to do fasted training?

The simplest time for most of us is first thing in the morning before you have any food.  This is because you would have been fasting for at least 8 hours (we hope) while you sleep so your insulin levels will be low.

Once you train you can have your post-workout meal and get on with your day without having to worry about fasting later on.  It also means your workout is done and dusted for the day and you have started on a positive note.

If you cant train in the morning then just try to leave at least 4 hours after eating before you train so that your body has a good chance of having low insulin levels and you are in a more fasted state. 

If you are new to fasted training I recommend starting with shorter workouts rather than throwing yourself into a long-distance workout straight away until you get used to this new training style.  Fasted cardio isn't for everyone so build it up slowly.  If you feel light-headed or dizzy make sure you stop immediately. 

It's important for me to mention that fasted cardio is just one way you facilitate fat loss and many people have used it successfully and others not so successfully.

There are many studies for and against the fact that fasted cardio can burn fat faster than non fasted but there are also many arguments against this.  So it comes down to you, your lifestyle, and what regime you can follow consistently.

Most people who perform fasted cardio have a goal of fat loss and when you perform fasted cardio alongside a calorie deficit nutrition plan you can get some great results.


Aaron Collins-Thomas

Founder of TONIQ

Have you tried fasted cardio?  What has worked well for you?  Let us know in the comments below.  Share this with someone who you know would benefit from reading this.  The U Perform family loves sharing ideas and encouraging each other.