What Is Fasted Cardio
Lose Weight Quicker With Fasted Cardio
Heard of fasted cardio? People seem to be extolling the virtues of this craze everywhere, convinced that doing cardio on an empty stomach helps you drop the pounds quicker.
But as usual – there’s more than meets the eye with this one: while fasted cardio can be a powerful tool in helping you shift stubborn fat, it needs to be done correctly. After all, you don’t want to end up burning muscle – or burning nothing at all.
Fasted Cardio – The Facts
First things first, fasted cardio means more than simply working out without any fuel in the tank. Fasted cardio is cardio that’s done in a fasted state. Here’s what that means…
When you eat food, the body breaks it down into a stack of different molecules like amino acids, fatty acids and glucose. These are absorbed into the blood where they are joined by insulin, which transports these molecules to the cells.
How long this takes depends on the size of your meal – while the body is processing the food, it’s in a post-prandial state, which means insulin levels are higher than normal. Once the body is finished doing this, it’s in a post-absorptive or fasted state, and insulin levels revert to their baseline level. This happens throughout the day.
So while your stomach may feel empty and hour after your meal, it’ll be another two or three hours until you hit a fasted state. In other words, you should be thinking of fasted cardio as a question of ‘fed or fasted’? Rather than ‘hungry or empty’?
To keep this super simple:
- If you do cardio while you’re body is still processing food and insulin levels are high, this is fed cardio
- If you do cardio once you’re body is done processing food and insulin levels are low, this is fasted cardio.
Fasted Cardio And Fat Loss
Exercising while the body is in a fasted state has proven in numerous studies to increase both:
- Lipolysis – the breakdown of fat cells for energy
- Oxidation – the burning of energy by cells
In short, this means that if you exercise when insulin is at a baseline level, your body will mobilise and burn more fat than it would normally… bingo!
Other studies have highlighted that blood flow in the abdominal region is increased when you’re in a fasted state. Why is this important? Because one of the key reasons why stubborn belly fat is so hard to shift is because of reduced blood flow, and therefore less fat-burning chemicals, in this region.
Fasted Cardio: When’s Best?
Research by the British Journal of Nutrition has highlighted that doing fasted cardio in the morning can see people burn up to 20% more fat. And there are plenty more to back that up.
This is because as you sleep, the body conserves its carb stores and uses fat to fuel the body. It also breaks amino acid down into glucose, so doing fasted cardio in the morning is likely to mobilise both muscle and amino acid for fuel.
While this is great news for fat loss, it can be trickier for those looking to build muscle – taking a fast-digesting protein like whey, alongside slow-digesting casein, after working out should allay any issues here, however.
The Downside Of Fasted Cardio
It’s not all good news though – as mentioned above, fasted cardio can increase muscle breakdown rates, and if you damage too many muscle cells when working out, the body simply can’t keep up with repairing them all.
What’s more, exercising when insulin levels are low can make it harder to focus and maintain energy, meaning you’re unlikely to reach the same level of workout intensity, and thus burn as many calories, as ordinary workouts.
If you’re looking for the fat burning benefits of fasted cardio without the cons, we recommend high intensity interval training (HIIT). Studies show that HIIT workouts can see twice the total fat loss of fasted cardio – this is because this type of workout continues to burn calories and fat throughout the day.
The bottom line? While fasted cardio works, and can be a powerful tool for losing weight quickly, it’s not great for maintaining muscle. So if that’s your focus, give HIIT a try.