So, does fasted cardio burn more calories generally, and do we even have to do that type of cardio?
Those exact few questions have been repeated over and over again and the information about the m is often contradicting.
Some people swear by its effectiveness and others don’t even find the slightest of difference between fasted and non-fasted cardio.
There’s also a third group of people, who totally deny any form of cardio, as according to them, it will “Burn all their muscle”.
The last one is a result of ignorance, so if you want to learn more about that, check out our “Cardio guide”.
While you may often see contradicting opinions, the truth is somewhere in-between.
So, for example, if you hear two different people say “Fasted cardio burns muscle” and “Fasted cardio burns fat”, well, both are true.
However, that is so, under different conditions, meaning that fasted cardio is not the only factor that results in that certain outcome.
Ultimately, considering and analyzing those hidden, additional factors will lead us to the ultimate truth.
Why do fasted cardio?
This type of cardio is preached by many competitive athletes and especially athletes that have a main goal of looking at their best come competition day.
The concept of morning fasted cardio is quite simple and straightforward-
After having slept for 8 hours and logically, not consuming any food, we have limited amounts of glucose in our blood, meaning that we deplete it way quicker, once we start doing cardio in a fasted state.
Once that blood sugar (glucose) is depleted, our body’s second resort is the fat tissue, which starts breaking down to grant energy for the cardio activity we are doing.
Another benefit is that after eating, insulin levels are higher, which in turn results in a lower rate of fat burning.
“When the body is in a fasting state, several backup mechanisms ensure your muscles and brain get the necessary sugar for fuel. During exercise, after your body’s sugar stores are exhausted, the body then taps into stored fat and turns that into sugar or turns protein from muscle into sugar.” Harvard health publishing (1)
Now, that’s the theory, but of course, in order to connect theory with practice, we need to apply that theory and yield results, so let’s take a closer look.
What does practice have to say about fasted cardio?
At one point, many people decide it is time to take their body and health together and lose some weight.
Generally, people resort to fancy, 30-day challenges, fad diets and excessive, exhausting cardio sessions.
But does fasted cardio have an actual effect?
Well, the answer is – Yes and no.
Different things work differently for different individuals, and as we already mentioned, there are other factors too.
Fasted morning cardio, as already mentioned is a big tool in the arsenal of many competitive athletes, and that type of training is not a 21st century thing, it is a relatively old concept.
So, if it something so effective, why do some people gain its benefits while others seem to stagnate?
- Competitive athletes have everything in check
They know how many calories they burn, they know exactly how many calories they consume.
They have a strict weekly schedule and a strict training regimen.
The more you monitor, the more you know your body and hence, the more you progress.
So, before asking why fasted cardio didn’t magically make you lose all that fat, check your diet, it may be off.
If you’ve checked it and you still don’t lose fat, double check it. There is no way you would be doing everything right and not progress.
- Competitive athletes are okay with the losses.
During the process of fat loss, we experience many inconveniences: Hunger, cravings, loss of sex drive, etc.
Most people give in and ruin their diet with massive cheat days, which in the end, confuse the metabolism and everything returns to the initial state.
That is to say that if you want to lose fat consistently, you have to stay devoted and consistent to both your nutrition and training plan
Science & fasted cardio
Before we say anything else, let’s mention the MOST IMPORTANT factor, which will ultimately determine your fat loss rate: The energy balance.
If in the end of the day, you have consumed more calories than you require to maintain your body weight, given your individual characteristics and activity levels.
Guess what- You won’t lose weight.
If a CONSISTENT caloric deficit is not present, we will not burn fat, whether we do fasted or full-tummy cardio.
So, ultimately, that’s the biggest factor – Nutrition.
As hard as it is for you to swallow, we’ll be blunt: To achieve healthy fat loss, you MUST track your nutrition, as workouts can’t compensate for s*#tty habits.
So, no matter the scientific researches that test the benefits of fasted cardio on different individuals, with different individual characteristics, we can one thing, that is relevant for EVERYONE:
Fasted cardio burns more fat if there is a consistent caloric deficit!
Now, before we wrap this up, let’s compare fasted cardio to other types of cardio
As we already mentioned, there is no definitive answer to the question “When is it best to do cardio?”, as it is different for everyone.
However, let’s compare fasted cardio to other types of cardio and help you pick one.
Keep in mind, each has pros and cons.
- Cardio before weights
We generally recommend cardio before weights as a light warm-up.
That means, no more than 5 to 10 minutes of low-intensity cardio, that will help you improve blood flow and raise the heart rate slightly.
All of this will lead to a good warm-up and be used as a preventative measure against injuries.
What we recommend is avoiding excessively long cardio sessions prior to resistance training, as that will severely deplete your muscle glycogen stores and lead to a sub-optimal resistance training workout afterwards.
- Post-workout cardio
After resistance training, we observe a substantial depletion of the muscle glycogen stores.
Glycogen of course, is the biggest source of fuel for the muscles during physical activities.
So, once that is depleted, the body starts utilizing other means of energy releasing, namely, using the fat reserves.
However, it is well known that extensive cardio not only uses fats and liver glycogen, but also proteins, meaning you’re at risk of muscle loss.
And you don’t want that do you?
That is exactly why we recommend no more than 15-25 minutes of cardio after resistance training, done 2-3 times weekly.
- Fasted cardio
We talked about this up until now.
We cleared out that it is highly beneficial, but also not as effective if other factors such as nutrition are not covered.
We generally recommend fasted morning cardio to people who have little to no time during the rest of the day.
Also, morning cardio would be the perfect biochemical boost to kickstart your day.
As a whole, we don’t recommend excessively high intensity cardio sessions in the morning, especially during a period of weight loss, however, low to moderate intensity jogging or even walking in the morning would be a perfect start.
- Night time cardio
This is also a good option for people who are busy throughout the day.
If you do your resistance training first and then cardio at noon, this is your go-to choice.
Make sure to not excessively stuff yourself with food during the hours prior to your sessions and don’t fall asleep immediately after eating/training.
Allow your body to relax, digest and only then, rest yourself to sleep easily. This is also a good option for you if you are not a morning person.
So, is fasted cardio king and when is it best to do cardio?
Well, fasted cardio certainly has its benefits but it is no magic and obeys other rules, such as the rules of energy balance.
If you eat less than you burn, you will burn fat, no matter what type of training you do.
Ultimately, your goal should be to fit your cardio and resistance training sessions well within your weekly schedule, so that you can devote the time to it completely, rather than bash through the workouts.
Lastly, again, we would advise you to avoid extensive cardio prior to a resistance training session or a big meal.
Stay lean, stay healthy!